A big chunk of Arizona became part of US 169 years ago. What to know about the Gadsden Purchase (2024)

Nearly 170 years ago this week, Mexico sold a substantial chunk of what is now Arizona to the United States. The purchase included the Arizona cities — then small towns — of Yuma, Tucson and Casa Grande, plus Las Cruces, New Mexico. It also allowed the United States to avoid paying a fortune for Native American raids into Mexico.

Here's what to know about the Gadsden Purchase:

What was the Gadsden Purchase and when did it happen?

The Gadsden Purchase was the last big parcel of land acquired in the Lower 48 states, comprising 30,000 square miles of prime Sonoran Desert that was formerly considered a "no man's land" in northern Mexico. It followed the acquisition and purchase — or theft, depending on the point of view — of more than half of Mexico as part of the Treaty of Guadalupe Hidalgo following the end of the U.S.-Mexico War in 1848.

The deal added to what was then called the Territory of New Mexico, a land where slavery of Black, white, Hispanic and Indigenous people was common until after the Civil War.

The purchase is named after James Gadsden, the ambassador who negotiated it at the request of President Franklin Pierce. He was the grandson of Christopher Gadsden, a brigadier general during the American Revolution who created the popular Gadsden flag that features a rattlesnake above the apostrophe-less phrase "Dont Tread On Me."

Gadsden and Mexican president-turned-dictator Antonio López de Santa Anna signed an initial $15 million deal in 1853. But that deal was later changed, resulting in a revised sale for $10 million signed in Mexico City on June 8, 1854 — making this year its 169th anniversary.

Why did Mexico sell the land?

Pierce and Gadsden, a secessionist and former railroad executive, were interested in acquiring the parcel to build a southern rail line that would stretch from the shores of the Atlantic Ocean to the Pacific, and because of potential mining riches. Pierce's secretary of war, future Confederate President Jefferson Davis, urged Pierce to make the purchase.

Meanwhile, Santa Anna wanted to sell the land to pay troops to fight rebels. Mexico also wanted the United States to pay claims for damages by Indigenous people who had stepped up cross-border raids following the U.S.-Mexico War and had taken numerous hostages back across the border to the New Mexico territory; the United States had agreed to do this in the treaty that ended the war between the two countries.

The official reason for the negotiations was to solve the problem of a disputed border line between Mexico and the United States in Mesilla Valley in what is now New Mexico. In Mexico, the Gadsden Purchase is called Venta de La Mesilla, for the Sale of La Mesilla.

Why didn't the United States try to buy Rocky Point, too?

President Pierce instructed Gadsden to pay up to $50 million for various options, including the potential to buy a larger parcel of land that would have included shoreline access to the Gulf of California. (The town of Puerto Peñasaco didn't yet exist back then.) Santa Anna refused based on the fact that extending the new U.S.-Mexico border to the gulf would have cut off access to Baja California, although Gadsden also was prepared to buy Baja California, too.

Mexicans weren't keen on giving away too much more land, either, after losing more than half their country and Texas following the war. But Santa Anna agreed to the smaller parcel that now marks the current U.S.-Mexico border.

Santa Anna found the deal personally costly, however, according to Alexander Aviña, an Arizona State University associate professor: "It helped spark the Ayutla Revolution that overthrew (Santa Anna) for the final time in 1854-1855."

What else did the United States get in the deal?

An often-overlooked aspect of the Gadsden Purchase was that it allowed the United States to get out of its agreement to reimburse and help Mexicans affected by indigenous attacks, Aviña noted.

"Between 1848-1853, U.S. officials had recognized that they could not stop such raids," Aviña said, adding that such raids continued until the late 19th century.

He referenced the work of historian Brian DeLay of the University of California, Berkeley, who said in a 2010 paper that the United States, "threatened with massive lawsuits from the Mexican landholders who had lost so much to raiding after 1848, the United States bought its way out of Article 11" of the post-war treaty in the revised version of the Gadsden Purchase signed in 1854.

What about that railroad?

Tensions over slavery before the Civil War derailed the railroad plan for decades. The Second Transatlantic Railroad was finally completed in August 1883.

Reach the reporter atrstern@arizonarepublic.comor 480-276-3237. Follow him on Twitter@raystern.