Gadsden Purchase: Definition & Summary

Instructor: Christina Boggs

Chrissy has taught secondary English and history and writes online curriculum. She has an M.S.Ed. in Social Studies Education.

During the 1840s and 1850s, the United States and Mexico had a good deal of conflict, which eventually led to the Gadsden Purchase made in 1854. This lesson explains the origins and outcomes of the deal.

Conflict with Mexico

Did you know that the United States fought a war against Mexico? During the 1840s, the United States annexed the recently independent Republic of Texas and brought it under American protection. This did not sit well with Mexico, who for years had control over the territory. The two countries also fought over where the border of Texas actually started. The Mexican-American War came to an end in 1848 with the Treaty of Guadalupe Hidalgo. Unfortunately, the conflict between the two countries continued.

For starters, the U.S. and Mexico could not agree on who had the right to the Mesilla Valley, a stretch of land along the Rio Grande between present-day New Mexico and Texas. The United States wanted this land to build an offshoot of the transcontinental railroad.

At the same time, the Treaty of Guadalupe Hidalgo required the U.S. to protect Mexico from any attacks by Native Americans living in the area. Mexico claimed that the U.S. was not only responsible for protection, but for compensating them for any damage that the Native Americans caused. The U.S. refused to pay for damages, further angering the Mexican government.

Tensions Rise

In 1853, things became even more heated between the U.S. and Mexico. That year, the Mexican government decided to kick out any Americans living in the Mesilla Valley. The governor of the New Mexico Territory reacted by claiming the Mesilla Valley as part of New Mexico. In response, Mexican President Antonio de Santa Anna mobilized the Mexican military and sent them into the Mesilla Valley. To deal with the growing crisis in the Southwest, President Franklin Pierce sent the U.S. Minister to Mexico, James Gadsden, to broker a deal with Mexico.

Mexican President Antonio de Santa Anna
Mexican President Antonio de Santa Anna

The Gadsden Purchase

James Gadsden was sent to Mexico with several points of negotiation as well as a wide budget. He was authorized to offer Mexico up to $50 million for California and as much as $15 million for the part of northern Mexico that the U.S. wanted for a railroad. While Santa Anna refused to sell California, he was willing to give up a part of Mexico's northern territory.

Santa Anna agreed to sell 45 thousand square miles of land to the tune of $15 million. In addition, the United States agreed to continue doing their best to protect Mexico from Native American attacks, while Mexico agreed to no longer hold them financially liable for any damages. Gadsden and the Mexican president signed this initial agreement on December 30, 1853.

James Gadsden
James Gadsden

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