Which territory did the United States gain from the Mexican-American War?

• A. Florida and Georgia
• B. Oregon
• C. California and much of the Southwest
• D. Alaska

Answer: (C)

This question is about how the Mexican-American War reshaped the United States. After the war, the United States gained California and much of the Southwest—territory that today includes California, Nevada, Utah, Arizona, New Mexico, and parts of Colorado and Wyoming. The victory led to the Treaty of Guadalupe Hidalgo in 1848, which ceded this vast area to the U.S. and set the border along the Rio Grande for Texas, while the U.S. also paid Mexico $15 million and took on some Mexican debts. This expansion helped fulfill the era’s westward ambitions and set the stage for events like the California Gold Rush.

Other options reflect land gained through different events: Florida and Georgia were acquired earlier in U.S. history; Oregon came through the Oregon Treaty with Britain; Alaska was purchased later, in 1867.