West Texas Acquisition: Treaty of Guadalupe Hidalgo (1848)

Mexican Cession Brought the Region into the U.S.

Most of West Texas was acquired via the Treaty of Guadalupe Hidalgo (February 2, 1848), ending the Mexican–American War.

Terms

• Mexico ceded ~525,000 sq mi (55% of its territory).
• Included present-day California, Nevada, Utah, Arizona, New Mexico, parts of Colorado, Wyoming—and Texas west of the Nueces River (Mexico had claimed the Nueces as boundary; U.S. claimed Rio Grande).
• U.S. paid $15 million + assumed $3.25M in Mexican debts to U.S. citizens.

Subsequent Clarification

The Gadsden Purchase (1854) added a small strip south of the Gila River (southern AZ/NM), not West Texas. The Rio Grande boundary was confirmed, securing El Paso and the Trans-Pecos for the U.S.