---
title: "AP Human Geography Unit 6 Review: Cities and Urban Land-Use"
description: "AP Human Geography Unit 6 covers The Origin and Influences of Urbanization and Cities Across the World. Study guides, practice questions, and key terms."
canonical: "https://fiveable.me/ap-hug/unit-6"
type: "unit"
subject: "AP Human Geography"
unit: "Unit 6 – Cities and Urban Land–Use"
---

# AP Human Geography Unit 6 Review: Cities and Urban Land-Use

## Overview

Unit 6 examines cities from their origins to their modern challenges. You will explain why cities form where they do, compare models of urban structure, analyze how world cities drive globalization, and evaluate responses to problems like sprawl, housing discrimination, and environmental degradation.

## AP CED Alignment

This unit hub is organized around AP Course and Exam Description topics, skills, and exam task types when they are available in the source data.
- 6.1: The Origin and Influences of Urbanization
- 6.2: Cities Across the World
- 6.3: Cities and Globalization
- 6.4: The Size and Distribution of Cities
- 6.5: The Internal Structure of Cities
- 6.6: Density and Land Use
- 6.7: Infrastructure in Urban Development
- 6.8: Urban Sustainability
- 6.9: Urban Data
- 6.10: Challenges of Urban Changes
- 6.11: Challenges of Urban Sustainability
- 6.1: Why Cities Form and Grow
- 6.2: Megacities, Edge Cities, and New Urban Forms
- 6.3: World Cities and Globalization
- 6.4: City Size, Distribution, and Hierarchy
- 6.5: Models of Urban Internal Structure
- 6.6-6.7: Density, Land Use, and Infrastructure
- 6.8: Urban Sustainability Design
- 6.9: Urban Data: Quantitative and Qualitative
- 6.10: Urban Challenges: Housing, Discrimination, and Fragmented Government
- 6.11: Urban Sustainability Challenges and Responses
- Skill Category 4 - Source Analysis
- FRQ 1 – No Stimulus
- FRQ 2 – One Stimulus
- FRQ 3 – Two Stimuli

## Topics

- [6.1: The Origin and Influences of Urbanization](/ap-hug/unit-6/origin-influences-urbanization/study-guide/pAzv431CVNgIgWsXY5AT): Explains how site and situation shape where cities form, and how transportation, migration, economic development, and government policy drive urbanization and suburbanization.
- [6.2: Cities Across the World](/ap-hug/unit-6/cities-across-world/study-guide/QAwLNSgI03JPsEeMON7L): Covers megacities and metacities concentrated in the periphery and semiperiphery, and the new suburban forms, including edge cities, exurbs, and boomburbs, produced by decentralization.
- [6.3: Cities and Globalization](/ap-hug/unit-6/cities-globalization/study-guide/R8Dz2BPSfMV0U4ExFNFz): Explains how world cities sit at the top of the global urban hierarchy and drive globalization through financial, transportation, and digital networks.
- [6.4: The Size and Distribution of Cities](/ap-hug/unit-6/size-distribution-cities/study-guide/vqLB2qOc3TvB7zaS7TTB): Applies the rank-size rule, primate city concept, gravity model, and Christaller's central place theory to explain how cities are sized, spaced, and connected.
- [6.5: The Internal Structure of Cities](/ap-hug/unit-6/internal-structure-cities/study-guide/bmmlitd92K8BXI98qRxQ): Compares the Burgess, Hoyt, multiple-nuclei, and galactic city models alongside bid-rent theory and regional models for Latin America, Southeast Asia, and Africa.
- [6.6: Density and Land Use](/ap-hug/unit-6/density-land-use/study-guide/bSPYlL5bBF2XQv4I6E4E): Describes how low-, medium-, and high-density residential patterns reflect a city's culture, technology, and development history, including infill development.
- [6.7: Infrastructure in Urban Development](/ap-hug/unit-6/infrastructure-urban-development/study-guide/nez2tBKJMblwbts0qHJm): Explains how the location and quality of roads, transit, water, and utilities shape economic and social development and reflect political power, including the legacy of redlining.
- [6.8: Urban Sustainability](/ap-hug/unit-6/urban-sustainability/study-guide/eQDrKhXlpgFYUb73N8FQ): Covers mixed land use, walkability, transit-oriented development, New Urbanism, greenbelts, and smart growth, including both the benefits and criticisms of these design approaches.
- [6.9: Urban Data](/ap-hug/unit-6/urban-data/study-guide/WwyCj47kBX58APegXtT2): Distinguishes quantitative data (census, ACS, census tracts) from qualitative data (field studies, interviews) and explains how each is used to analyze urban change.
- [6.10: Challenges of Urban Changes](/ap-hug/unit-6/challenges-urban-changes/study-guide/sndQsKKtXtnNdW94sf5d): Addresses redlining, blockbusting, housing affordability, squatter settlements, environmental injustice, gentrification, and fragmented government as causes and effects of urban change.
- [6.11: Challenges of Urban Sustainability](/ap-hug/unit-6/challenges-urban-sustainability/study-guide/SQ69AjpGq5hZEHHzzK8g): Identifies sprawl, sanitation, climate change, air and water quality, ecological footprint, and energy use as sustainability challenges, and evaluates responses including brownfield redevelopment and urban growth boundaries.

## Hardest Topics And Analytics

Snapshot: practice snapshot
This snapshot uses Fiveable practice activity to show where students tend to miss questions and which review moves are worth prioritizing first.
- **69% average MCQ accuracy** (Across 42k multiple-choice practice attempts for this unit.)
- **42k MCQ attempts** (Practice activity included in this snapshot.)
- **67% average FRQ score** (Across 157 scored free-response attempts for this unit.)
- **6.6: Density and Land Use**: 35% MCQ miss rate across 4507 attempts. Review Density and Land Use with attention to how the concept appears in AP-style source and evidence questions.
- **6.11: Challenges of Urban Sustainability**: 34% MCQ miss rate across 3266 attempts. Review Challenges of Urban Sustainability with attention to how the concept appears in AP-style source and evidence questions.
- **6.9: Urban Data**: 32% MCQ miss rate across 5747 attempts. Review Urban Data with attention to how the concept appears in AP-style source and evidence questions.
- **6.10: Challenges of Urban Changes**: 31% MCQ miss rate across 3272 attempts. Review Challenges of Urban Changes with attention to how the concept appears in AP-style source and evidence questions.

## Review Notes

### 6.1: Why Cities Form and Grow

Cities originate where site and situation make settlement and growth possible. Site is the physical character of a place, such as a defensible hilltop, fertile floodplain, or natural harbor. Situation is a place's connectivity to other places, such as being at a river confluence or along a trade route. Once established, cities grow because of changes in transportation, population growth, rural-to-urban migration, economic development, and government policy.

- **Site**: The physical characteristics of a location, such as terrain, water access, or natural resources, that make it suitable for settlement.
- **Situation**: A city's location relative to surrounding places and its connections through trade routes, transportation, or communication networks.
- **Suburbanization**: The movement of people and economic activity from city centers to surrounding suburban areas, driven by transportation improvements and government policies like highway construction.
- **Industrialization**: The shift to factory-based manufacturing that concentrated workers in cities and accelerated urban growth in the 19th and 20th centuries.

**Checkpoint:** Can you explain how a city's site and situation each contributed to its origin, and name two forces that drive continued urban growth?

Concept | Definition | Example
--- | --- | ---
Site | Physical features of the location itself | New Orleans on the Mississippi River delta
Situation | Connectivity to surrounding places | Chicago as a railroad hub linking East and Midwest

### 6.2: Megacities, Edge Cities, and New Urban Forms

Urbanization produces different outcomes depending on where it occurs. Megacities exceed 10 million people and are increasingly found in periphery and semiperiphery countries such as Lagos, Dhaka, and Mumbai. Metacities exceed 20 million. In wealthier countries, suburbanization and decentralization have created edge cities, exurbs, and boomburbs. These new forms bring challenges including automobile dependence, sprawl, and uneven service provision.

- **Megacity**: An urban area with more than 10 million people, increasingly concentrated in the Global South.
- **Edge Cities**: Large suburban nodes with significant office, retail, and employment space that developed outside traditional city centers, such as Tysons Corner, Virginia.
- **Suburban Sprawl**: Low-density, automobile-dependent expansion of residential and commercial development into previously undeveloped land at the urban fringe.
- **Exurban Area**: A low-density area beyond the suburbs where residents commute to the city but live in a more rural setting.

**Checkpoint:** What distinguishes a megacity from a metacity, and what distinguishes an edge city from a traditional suburb?

Urban Form | Key Characteristic | Where Most Common
--- | --- | ---
Megacity | Population over 10 million | Periphery and semiperiphery countries
Metacity | Population over 20 million | Global South (e.g., Tokyo, Delhi)
Edge City | Major employment and retail outside CBD | Core countries, especially the US
Boomburb | Fast-growing large suburb with suburban character | US Sun Belt (e.g., Mesa, Arizona)
Exurb | Low-density beyond suburbs, long commutes | Outer rings of US metro areas

### 6.3: World Cities and Globalization

World cities, also called global cities, sit at the top of the global urban hierarchy and serve as command-and-control centers for the global economy. Cities like New York, London, and Tokyo concentrate advanced producer services, transnational corporation headquarters, and financial markets. They are connected to each other and to lower-order cities through transportation networks, digital infrastructure, and trade flows, allowing them to shape and mediate global economic and cultural processes.

- **Global City**: A city that functions as a major node in the global economy, concentrating finance, corporate headquarters, and advanced services. Examples include New York, London, and Tokyo.
- **Urban Hierarchy**: The ranking of cities by size, function, and influence, from small towns to regional centers to global cities.
- **Time-Space Compression**: The way transportation and communication technology reduces the effective distance between places, enabling cities to maintain global connections.

**Checkpoint:** How do world cities differ from other large cities, and what kinds of networks connect them to the rest of the world?

### 6.4: City Size, Distribution, and Hierarchy

Four concepts explain how cities are sized and distributed within a country or region. The rank-size rule predicts that the second-largest city will be half the population of the largest, the third will be one-third, and so on. A primate city dominates its country disproportionately, often holding more than twice the population of the next largest city. Christaller's central place theory explains how cities are spaced based on the threshold and range of services they provide. The gravity model predicts that interaction between two cities increases with population size and decreases with distance.

- **Primate City**: A country's largest city that is disproportionately larger and more influential than all other cities in that country, such as Paris in France or Bangkok in Thailand.
- **Central Place Theory**: Christaller's model explaining that settlements are distributed in a hierarchy based on the threshold population needed to support a service and the range customers will travel to reach it.
- **Gravity Model**: A model predicting that interaction between two places is proportional to their populations and inversely proportional to the distance between them.
- **Market Area**: The surrounding region from which a central place draws customers for its goods and services, also called a hinterland.

**Checkpoint:** If a country has a primate city, what does that tell you about its urban system compared to a country that follows the rank-size rule?

Concept | What It Explains | Key Prediction
--- | --- | ---
Rank-size rule | Relative size of cities in a system | 2nd city = 1/2 the largest; 3rd = 1/3
Primate city | Dominance of one city | Largest city far exceeds all others
Central place theory | Spacing and hierarchy of settlements | Larger centers spaced farther apart
Gravity model | Interaction between cities | More interaction with larger, closer cities

### 6.5: Models of Urban Internal Structure

Several models describe how land use is arranged inside a city. The Burgess concentric-zone model places the CBD at the center, surrounded by rings of transition, working-class housing, middle-class housing, and commuter zones. The Hoyt sector model argues that land uses extend outward in wedges along transportation corridors. The Harris and Ullman multiple-nuclei model recognizes that cities develop around several specialized centers rather than one CBD. The galactic city model describes car-dependent cities where edge cities orbit a weakened downtown. Bid-rent theory explains that land values fall with distance from the CBD, shaping which users locate where. Regional models for Latin America, Southeast Asia, and Africa reflect how colonial history, informal settlements, and port-based development produce different spatial patterns.

- **Burgess Concentric Zone Model**: A model showing cities growing outward in concentric rings from the CBD, with each ring representing a different land use and socioeconomic group.
- **Sector Model**: Hoyt's model in which land uses extend outward from the CBD in wedge-shaped sectors along transportation routes rather than in uniform rings.
- **Multiple Nuclei Model**: Harris and Ullman's model showing cities organized around several specialized activity centers rather than a single CBD.
- **Bid-Rent Theory**: The principle that land values and the willingness to pay for land decrease as distance from the CBD increases, determining which land uses locate where.
- **Galactic City Model**: A model describing decentralized cities where edge cities and suburban nodes orbit a weakened central core, connected by highways rather than transit.

**Checkpoint:** Which model best describes a city with multiple downtowns and specialized districts, and how does bid-rent theory explain the pattern of land uses you would see moving outward from a CBD?

Model | Core Idea | Best Applies To
--- | --- | ---
Burgess concentric zone | Rings of land use from CBD outward | Early 20th-century industrial cities
Hoyt sector | Wedges along transit corridors | Cities shaped by rail and streetcar lines
Multiple nuclei | Several specialized centers | Large, complex modern cities
Galactic city | Edge cities orbiting weak core | Car-dependent US cities post-1970
Griffin-Ford Latin American | Commercial spine, elite sector, squatter periphery | Latin American cities

### 6.6-6.7: Density, Land Use, and Infrastructure

Residential density ranges from low-density single-family homes in suburbs to high-density apartment towers near city centers. These patterns reflect a city's culture, technology, and development history. Infill development adds housing on vacant lots within existing urban areas rather than expanding outward. Infrastructure, including roads, transit, water, sewer, and utilities, directly shapes where economic and social development occurs. Infrastructure decisions reflect political power: historically, redlining denied investment to minority neighborhoods, and highway construction displaced urban communities. The quality and location of transit, water, and sanitation infrastructure still produce unequal spatial outcomes today.

- **Built Environment**: The human-made physical surroundings of a city, including buildings, roads, parks, and utilities, which reflect social values and economic priorities.
- **Urban Infrastructure**: The physical systems a city depends on, including transportation, water supply, sewage, and energy networks, whose location and quality shape economic and social development.
- **Gentrification**: The process by which higher-income residents move into lower-income urban neighborhoods, raising property values and often displacing long-term residents.

**Checkpoint:** How does the quality and location of infrastructure reflect political and social power in a city?

### 6.8: Urban Sustainability Design

Urban sustainability initiatives aim to reduce sprawl, improve walkability, and create more livable cities. Key tools include mixed land use, transit-oriented development, smart growth policies, New Urbanism, greenbelts, and slow-growth cities. Supporters argue these approaches reduce car dependence, improve housing diversity, and lower environmental impact. Critics point out that they can raise housing costs, create de facto segregation by income, and erase neighborhood character.

- **New Urbanism**: An urban design movement promoting walkable, mixed-use neighborhoods with human-scale design as an alternative to sprawl.
- **Smart Growth**: Planning policies that concentrate development in existing urban areas, preserve open space, and reduce automobile dependence through mixed uses and transit investment.
- **Transit-oriented development**: Compact, mixed-use development built around transit stations to reduce car dependence and encourage walkability.
- **Green Belts**: Designated open land around urban areas that limits outward sprawl and preserves agricultural and natural land.
- **Mixed Land Use**: Zoning that allows residential, commercial, and recreational uses in close proximity, reducing commute distances and supporting walkability.

**Checkpoint:** What is one specific criticism of New Urbanism or smart growth policies, and what evidence supports that criticism?

### 6.9: Urban Data: Quantitative and Qualitative

Geographers use two types of data to study urban change. Quantitative data from sources like the census, American Community Survey, and census tracts provide measurable information about population size, composition, housing tenure, and migration flows. Qualitative data from field studies, oral histories, interviews, and participant observation capture how residents experience and perceive urban change. On the AP exam, you may be asked to read choropleth maps, population pyramids, or census tables and explain what they reveal about urban patterns.

- **Census Data**: Systematic demographic information collected by governments, used to track population size, composition, and housing characteristics in urban areas.
- **Census Tract**: A small statistical subdivision of a county used to collect and compare demographic data at the neighborhood level.
- **Qualitative Data**: Non-numeric information from interviews, field observations, and narratives that captures residents' experiences and attitudes toward urban change.
- **Satellite Imagery**: Remote sensing images used to detect land use change, urban expansion, and environmental conditions in cities.

**Checkpoint:** Why would a geographer use qualitative data alongside census data when studying gentrification in a neighborhood?

Data Type | Source Examples | What It Shows
--- | --- | ---
Quantitative | Census, ACS, census tracts | Population size, housing tenure, income levels
Qualitative | Interviews, field studies, oral histories | Resident attitudes, lived experience of urban change

### 6.10: Urban Challenges: Housing, Discrimination, and Fragmented Government

As populations shift within cities, economic and social challenges intensify. Redlining was the practice of denying loans and investment to minority neighborhoods, producing lasting patterns of disinvestment. Blockbusting manipulated racial fears to profit from neighborhood transition. Zones of abandonment and disamenity zones emerge where disinvestment is severe. Squatter settlements form in cities where affordable housing is absent, especially in the Global South, creating land tenure conflicts. Responses include inclusionary zoning, community land trusts, and local food movements. Gentrification can revitalize neighborhoods but also displaces long-term residents. Fragmented government, where authority is split among city, county, and state agencies, makes coordinated responses difficult.

- **Squatter Settlements**: Informal housing built on land residents do not legally own, common in rapidly urbanizing cities in the Global South, often lacking basic services.
- **Favelas**: Informal settlements in Brazilian cities, characterized by self-built housing, limited infrastructure, and social marginalization.
- **Food Deserts**: Urban areas where residents lack convenient access to affordable, nutritious food, often linked to disinvestment in low-income neighborhoods.
- **De Facto Segregation**: Residential separation of groups that results from economic and social forces rather than explicit law, often reinforced by historical redlining and housing policy.

**Checkpoint:** Explain how redlining produced long-term spatial inequality in a city, and name one policy response designed to address housing access.

### 6.11: Urban Sustainability Challenges and Responses

Cities face major sustainability challenges including suburban sprawl, inadequate sanitation, climate change, poor air and water quality, large ecological footprints, and high energy use. The urban heat island effect raises temperatures in dense built-up areas. Brownfields are contaminated former industrial sites that require remediation before reuse. Responses include regional planning, brownfield redevelopment, urban growth boundaries, and farmland protection policies. Each response has trade-offs: urban growth boundaries can limit sprawl but raise housing costs inside the boundary.

- **Ecological Footprint**: The total land and water area required to produce the resources a city consumes and absorb its waste, a measure of urban environmental impact.
- **Brownfield**: Previously developed, often contaminated land that is abandoned or underused and targeted for environmental remediation and redevelopment.
- **Air Quality**: The condition of urban air in terms of pollutant levels, affected by vehicle emissions, industry, and urban density, and a key sustainability challenge for cities.
- **Sanitation**: Systems for safe waste disposal and clean water provision, whose absence in informal settlements creates major public health and environmental challenges.

**Checkpoint:** Match each urban sustainability challenge to one specific policy response and explain one limitation of that response.

Challenge | Policy Response | Limitation
--- | --- | ---
Suburban sprawl | Urban growth boundaries | Can raise housing costs inside boundary
Contaminated land | Brownfield remediation | Expensive and time-consuming
Farmland loss | Farmland protection policies | May restrict housing supply
Fragmented planning | Regional planning efforts | Requires cooperation across jurisdictions

## Study Guides

- [6.9 Urban Data](/ap-hug/unit-6/urban-data/study-guide/WwyCj47kBX58APegXtT2)
- [6.6 Density and Land Use](/ap-hug/unit-6/density-land-use/study-guide/bSPYlL5bBF2XQv4I6E4E)
- [6.5 The Internal Structure of Cities](/ap-hug/unit-6/internal-structure-cities/study-guide/bmmlitd92K8BXI98qRxQ)
- [6.7 Infrastructure in Urban Development](/ap-hug/unit-6/infrastructure-urban-development/study-guide/nez2tBKJMblwbts0qHJm)
- [6.2 Cities Across the World](/ap-hug/unit-6/cities-across-world/study-guide/QAwLNSgI03JPsEeMON7L)
- [6.3 Cities and Globalization](/ap-hug/unit-6/cities-globalization/study-guide/R8Dz2BPSfMV0U4ExFNFz)
- [6.11 Challenges of Urban Sustainability](/ap-hug/unit-6/challenges-urban-sustainability/study-guide/SQ69AjpGq5hZEHHzzK8g)
- [6.8 Urban Sustainability](/ap-hug/unit-6/urban-sustainability/study-guide/eQDrKhXlpgFYUb73N8FQ)
- [6.1 The Origin and Influences of Urbanization](/ap-hug/unit-6/origin-influences-urbanization/study-guide/pAzv431CVNgIgWsXY5AT)
- [6.10 Challenges of Urban Changes](/ap-hug/unit-6/challenges-urban-changes/study-guide/sndQsKKtXtnNdW94sf5d)
- [6.4 The Size and Distribution of Cities](/ap-hug/unit-6/size-distribution-cities/study-guide/vqLB2qOc3TvB7zaS7TTB)

## Practice Preview

### Multiple-choice practice

- **AP-style practice question**: Skill Category 4 - Source Analysis | A map shows a metropolitan area with a central city surrounded by multiple rapidly growing incorporated suburban cities, each with their own downtown commercial districts, schools, and services, with some suburban cities experiencing faster population growth than the central city. Which type of urban information is this visual identifying?
- **AP-style practice question**: Skill Category 4 - Source Analysis | Census maps show a Latin American city's poorest neighborhoods on steep hillsides and flood-prone lowlands while wealthier areas occupy flat, well-drained zones. Residents in hillside settlements say they chose those sites because land was affordable and available despite environmental risk. Which geographic process best explains this spatial pattern of inequality?
- **AP-style practice question**: Skill Category 4 - Source Analysis | Interviews in a postindustrial European city show nostalgia for manufacturing and concern about cultural loss. Census data record a 67 percent rise in service jobs and a 73 percent decline in manufacturing from 2000 to 2020. Maps show former factory districts now host galleries, restaurants, and tech offices. What do these qualitative and quantitative data together reveal about causes of urban geographic change?
- **AP-style practice question**: Skill Category 4 - Source Analysis | Residents report feeling threatened while census data show a 35% rise in median home values and a 40% decline in the original ethnic group's share over ten years. How do these qualitative and quantitative data together explain geographic change in the neighborhood?
- **AP-style practice question**: Skill Category 4 - Source Analysis | From 2000 to 2020 a metro area's suburbs grew 34% while the central city declined 8%. Satellite images show suburbs expanding onto former farmland while the central city gained residential density through infill and conversions. Which conclusion about metropolitan spatial change is best supported by these data?
- **AP-style practice question**: Skill Category 4 - Source Analysis | Satellite images show informal settlements expanding into flood-prone areas near industry. Census shows 62 percent of residents live on 18 percent of urban land. Field visits report no formal water, sanitation, or electricity. What do these sources reveal about causes of urban inequality?

### FRQ practice

- **Urban Patterns and Food Access**: FRQ 1 – No Stimulus | Urban Patterns and Food Access
- **Waste disposal and squatter settlement vulnerability**: FRQ 2 – One Stimulus | Waste disposal and squatter settlement vulnerability
- **FRQ 3 – Two Stimuli**: FRQ 3 – Two Stimuli

## Key Terms

- **Site vs. Situation**: Site is the physical character of a location, such as a harbor or floodplain. Situation is its connectivity to surrounding places through trade routes or transportation networks. Both shape a city's origin and growth.
- **Primate City**: A country's largest city that is disproportionately larger and more dominant than all others, such as Bangkok in Thailand or Paris in France, often concentrating political, economic, and cultural functions.
- **Central Place Theory**: Christaller's model explaining that settlements are distributed in a hierarchy based on the threshold population needed to support a service and the range customers will travel to access it.
- **Gravity Model**: A model predicting that interaction between two cities is proportional to their populations and inversely proportional to the distance between them.
- **Bid-Rent Theory**: The principle that land values and the willingness to pay for land decrease with distance from the CBD, determining which land uses, commercial, residential, or agricultural, locate at each distance.
- **Burgess Concentric Zone Model**: A model of urban structure showing the CBD at the center surrounded by concentric rings of transition zone, working-class housing, middle-class housing, and commuter zone.
- **Galactic City Model**: A model describing decentralized, car-dependent cities where edge cities and suburban nodes orbit a weakened central core, connected by highways rather than transit.
- **Global City**: A city that functions as a command-and-control center in the global economy, concentrating finance, corporate headquarters, and advanced producer services. Examples include New York, London, and Tokyo.
- **Megacity**: An urban area with more than 10 million people, increasingly located in periphery and semiperiphery countries such as Lagos, Dhaka, and Mumbai.
- **Gentrification**: The process by which higher-income residents move into lower-income urban neighborhoods, raising property values and often displacing long-term residents.
- **Squatter Settlements**: Informal housing built on land residents do not legally own, common in rapidly urbanizing cities in the Global South, typically lacking adequate water, sanitation, and electricity.
- **Smart Growth**: Urban planning policies that concentrate development in existing urban areas, preserve open space, and reduce automobile dependence through mixed uses, transit investment, and urban growth boundaries.
- **Brownfield**: Previously developed, often contaminated land that is abandoned or underused and targeted for environmental remediation and redevelopment rather than expansion into undeveloped land.
- **New Urbanism**: An urban design movement promoting walkable, mixed-use, human-scale neighborhoods as an alternative to low-density suburban sprawl.
- **Suburban Sprawl**: Low-density, automobile-dependent expansion of residential and commercial development into previously undeveloped land at the urban fringe, associated with long commutes and high infrastructure costs.

## Common Mistakes

- **Confusing site and situation**: Site is the physical character of the location itself, such as a river or harbor. Situation is about connections to other places. A city's port is a site feature; being at the intersection of two trade routes is a situation feature. Do not use the terms interchangeably.
- **Mixing up the urban land-use models**: The Burgess model uses concentric rings, the Hoyt model uses wedge-shaped sectors along transportation corridors, and the multiple-nuclei model has several specialized centers. A common error is describing the Hoyt model as having rings or the Burgess model as having sectors.
- **Treating the rank-size rule as universal**: Not every country follows the rank-size rule. Countries with a primate city, such as France or Thailand, have a first city far larger than the rule predicts. Be ready to identify which pattern a given country follows and explain why.
- **Describing gentrification as purely positive or purely negative**: The AP exam expects you to explain both consequences. Gentrification can reduce vacancy, attract investment, and improve infrastructure, but it also raises rents and displaces long-term lower-income residents. Always address both sides.
- **Confusing megacities with world cities**: A megacity is defined by population size, over 10 million people. A world city is defined by its economic function and global connectivity. Tokyo is both, but many megacities in the Global South are not world cities, and some world cities do not meet the megacity population threshold.

## Exam Connections

- **Explaining spatial patterns using urban models**: A common task in Unit 6 asks you to apply a specific urban model to a described or mapped city and explain why that model fits. Practice identifying which model applies by looking for clues: rings suggest Burgess, wedges along transit routes suggest Hoyt, multiple specialized districts suggest Harris and Ullman, and a decentralized highway-oriented layout suggests the galactic city model. You may also be asked to explain a limitation of a model, such as the fact that Burgess assumed a flat, uniform city with a single center.
- **Cause-and-effect reasoning about urban challenges**: Questions about topics 6.10 and 6.11 frequently ask you to explain the causes and effects of a specific urban process, such as redlining, gentrification, or suburban sprawl, and then evaluate a policy response. Structure your answers by naming the geographic cause, describing the spatial effect on the built environment or population, and then assessing whether a given response, such as inclusionary zoning or an urban growth boundary, effectively addresses that effect.
- **Interpreting maps and data about urban change**: The AP Human Geography exam regularly presents choropleth maps, census tables, population pyramids, or land use maps and asks you to describe a pattern and explain its geographic cause. For Unit 6, practice reading maps that show population density, housing tenure, income distribution, or infrastructure access and connecting what you see to concepts like bid-rent theory, redlining, or suburbanization. Be ready to distinguish what quantitative data shows from what qualitative data would add.

## Final Review Checklist

- **Unit 6 final review checklist**: Use this list to confirm you can handle every major skill and concept before your exam.
- **Explain site vs. situation**: Given a city's location, identify whether a factor is a site characteristic or a situation characteristic and explain how each influenced the city's origin or growth.
- **Compare urban land-use models**: Describe the Burgess, Hoyt, multiple-nuclei, and galactic city models and explain which best fits a given city's spatial pattern. Apply bid-rent theory to explain land value gradients.
- **Apply rank-size rule and central place theory**: Use the rank-size rule to predict city populations in a hierarchy, identify a primate city and explain its dominance, and apply threshold and range concepts from central place theory.
- **Distinguish megacities, edge cities, and world cities**: Explain what makes a city a megacity, an edge city, or a world city, and describe where each type is most commonly found and why.
- **Evaluate urban sustainability initiatives**: For New Urbanism, smart growth, transit-oriented development, and greenbelts, state at least one specific benefit and one specific criticism supported by geographic reasoning.
- **Explain urban challenges and responses**: Define redlining, blockbusting, gentrification, and squatter settlements. For each, explain a cause, a spatial effect, and at least one policy response such as inclusionary zoning or brownfield redevelopment.
- **Read and interpret urban data**: Distinguish quantitative from qualitative data sources, explain what census tracts and choropleth maps reveal about urban change, and describe when qualitative data adds information that quantitative data cannot provide.

## Study Plan

- **Step 1: Urbanization origins and global city forms**: Start with topics 6.1 and 6.2. Read the topic guides on site and situation and on megacities and edge cities. Make a two-column list of site factors and situation factors for three real cities. Then sketch the difference between a megacity, a boomburb, and an edge city in your own words.
- **Step 2: City size, distribution, and globalization**: Work through topics 6.3 and 6.4 together. Draw the urban hierarchy from small town to world city and place two real examples at each level. Practice applying the rank-size rule with a hypothetical country and identify whether a given country has a primate city or follows the rank-size pattern.
- **Step 3: Internal structure models**: Focus on topic 6.5. Draw each of the four main models from memory and label the zones. Then compare the Griffin-Ford Latin American model and the McGee Southeast Asian model to the Burgess model, noting what is different and why. Review bid-rent theory by sketching a land value gradient from CBD outward.
- **Step 4: Density, infrastructure, sustainability design, and urban data**: Cover topics 6.6, 6.7, 6.8, and 6.9 in one session. For density and infrastructure, connect housing type to bid-rent theory and explain how redlining shaped infrastructure investment. For sustainability, list the tools of smart growth and New Urbanism with one benefit and one criticism each. For urban data, practice distinguishing what a census table tells you versus what an interview reveals.
- **Step 5: Urban challenges and sustainability problems**: Finish with topics 6.10 and 6.11. Create a cause-effect-response chart for redlining, gentrification, squatter settlements, and suburban sprawl. For each sustainability challenge in 6.11, match it to a specific policy response and note one limitation. Use available practice questions to test your ability to explain these patterns in writing.

## More Ways To Review

- [Topic study guides](/ap-hug/unit-6#topics)
- [FRQ practice](/ap-hug/frq-practice)
- [Cram archive videos](/cram-archives?subject=ap-human-geography&unit=unit-6)
- [Cheatsheets](/ap-hug/cheatsheets/unit-6)
- [Key terms](/ap-hug/key-terms)

## FAQs

### What topics are covered in AP HuG Unit 6?

AP HuG Unit 6 covers urbanization and how cities form, grow, and function across 11 topics: The Origin and Influences of Urbanization, Cities Across the World, Cities and Globalization, The Size and Distribution of Cities, The Internal Structure of Cities, Density and Land Use, Infrastructure, Urban Sustainability, Urban Data, Challenges of Urban Changes, and Challenges of Urban Sustainability. Together these topics move from why cities first emerged to how modern cities handle growth, inequality, and sustainability. See the full breakdown at [/ap-hug/unit-6](/ap-hug/unit-6).

### How much of the AP HuG exam is Unit 6?

AP HuG Unit 6 makes up 12-17% of the AP exam, making it one of the heavier-weighted units. That percentage covers everything from urbanization and city models to the internal structure of cities, urban sustainability, and the challenges cities face today. Expect a solid handful of multiple-choice questions and possible FRQ coverage from this unit.

### What's on the AP HuG Unit 6 progress check (MCQ and FRQ)?

The AP HuG Unit 6 progress check in AP Classroom includes both MCQ and FRQ parts drawn from all 11 topics in the unit. The MCQ section tests concepts like urbanization patterns, city models, the internal structure of cities, density and land use, and urban sustainability. The FRQ part typically asks you to apply those models or analyze urban data in a specific context. To prep for the progress check, work through practice questions matched to each topic at [/ap-hug/unit-6](/ap-hug/unit-6). Focus especially on 6.5 The Internal Structure of Cities and 6.11 Challenges of Urban Sustainability, since those tend to generate the most analytical questions.

### How do I practice AP HuG Unit 6 FRQs?

AP HuG Unit 6 FRQs most often draw from urbanization processes, the internal structure of cities, urban sustainability, and challenges of urban change. These questions usually ask you to define a concept, apply a city-structure model like the Burgess Concentric Zone or Bid-Rent Theory to a real-world example, or analyze urban data. To practice, try these steps:
- Write out definitions for key models before applying them.
- Use actual city examples (not just generic ones) when explaining patterns.
- Practice reading and interpreting maps or graphs from 6.9 Urban Data.
- Check your responses against the scoring guidelines College Board releases for past exams. You can find FRQ-aligned practice tied to each topic at [/ap-hug/unit-6](/ap-hug/unit-6).

### Where can I find AP HuG Unit 6 practice questions?

For AP HuG Unit 6 practice questions, including multiple-choice and practice test sets, head to [/ap-hug/unit-6](/ap-hug/unit-6). There you'll find MCQ practice organized by topic, so you can target specific areas like urbanization, the internal structure of cities, or urban sustainability rather than reviewing everything at once. For the best results, mix topic-specific MCQ drills with timed full-unit practice tests as your exam date gets closer. That combination builds both accuracy and the pacing you need on test day.

### How should I study AP HuG Unit 6?

Start with urbanization in 6.1 and build forward, since every later topic connects back to why and how cities grow. Unit 6 rewards students who can apply models, not just name them, so practice sketching city-structure diagrams from memory and explaining what each zone represents. Here's a concrete study sequence:
1. Learn the major urban models (Concentric Zone, Sector, Multiple Nuclei, Latin American, etc.) and know which regions each fits.
2. Study the internal structure of cities alongside density and land use so those topics reinforce each other.
3. Connect 6.8 Urban Sustainability and 6.11 Challenges of Urban Sustainability, since FRQs often link problems to solutions.
4. Use 6.9 Urban Data to practice reading maps and graphs, a skill the exam tests directly.
5. Finish with timed MCQ sets from [/ap-hug/unit-6](/ap-hug/unit-6) to check your retention across all 11 topics. Spacing your review over multiple sessions beats cramming for a unit this concept-heavy.

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