The Mexican Period in New Mexico, from 1821 to 1846, marked a time of significant change. The Santa Fe Trail, opened in 1821, connected the region to the United States, sparking trade and cultural exchange. This era saw political shifts, economic growth, and increasing tensions between Mexico and the growing American presence. Key figures like William Becknell and Manuel Armijo shaped the period's events. The Santa Fe Trail's 900-mile route facilitated trade, cultural blending, and eventual U.S. expansion. The era ended with the Mexican-American War, leading to New Mexico's annexation by the United States in 1848.