History of the Southwestern United States
Gadsden Purchase
The Gadsden Purchase (Spanish: Venta de La Mesilla "La Mesilla sale"), also known as the Treaty of Mesilla, is a 29,640-square-mile (76,800 km2) region of present-day southern Arizona and southwestern New Mexico that the United States acquired from Mexico.
Treaty of Guadalupe Hidalgo
The Treaty of Guadalupe Hidalgo officially ended the Mexican–American War (1846–1848). It was signed on the 2nd of February 1848 in the town of Guadalupe Hidalgo. After the defeat of its army and the fall of the capital in September 1847, Mexico entered into peace negotiations with the U.S. envoy, Nicholas Trist.