Santa Fe is the capital city of New Mexico, established as a Spanish colonial settlement in 1610. It became significant in the context of the westward expansion of the United States, particularly during the Bear Flag Revolt and the military campaigns that followed, which contributed to California's integration into the Union. The city also played a critical role in the aftermath of the Treaty of Guadalupe Hidalgo, marking a pivotal moment in U.S.-Mexican relations and the territorial reconfiguration of the Southwest.