Mexico Ceded Half Its Territory to the U.S. in 1848 (Treaty of Guadalupe Hidalgo)

The Treaty of Guadalupe Hidalgo (1848), ending the Mexican–American War, transferred ~55% of Mexico's pre-war territory to the United States.

Territory Ceded (Present-Day States)

• California (entire)
• Nevada (entire)
• Utah (entire)
• Arizona (most, north of Gila River)
• New Mexico (most)
• Colorado (western slope)
• Wyoming (small SW corner)

Area: ~1.36 million km² (525,000 sq mi).
Payment: $15M + assumption of $3.25M in U.S. citizen claims against Mexico.

The 1853 Gadsden Purchase added southern Arizona/New Mexico (45,000 sq mi) for $10M for a southern railroad route.