Mexican-American War ends and U.S. acquires former Mexican territories

Mexico and the United States sign the Treaty of Guadalupe-Hidalgo, ending the Mexican-American War. The U.S. acquires California, a large area comprising New Mexico, Arizona, Nevada, Utah, and parts of Wyoming and Colorado. Mexicans in these annexed areas have the choice of returning to Mexico or receiving American citizenship with full civil rights: over 90% remain in the new American territories.