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2 February 1848Primary source · 2 sourcesWell documented

The Mexican-American War Ends With the Loss of Half the National Territory

The Treaty of Guadalupe Hidalgo cedes California, New Mexico, and Texas claims for fifteen million dollars

On the timeline · around 2 February 1848 · Independence and the Young RepublicIndependence and the Young RepublicThe Porfiriato and the RevolutionThe Mexican-American War Ends With the Loss of Half the National Territory18301835184018451850185518601865

Quick facts

War declared
13 May 1846
Treaty signed
2 February 1848, Guadalupe Hidalgo
Territory ceded
c. 55% of Mexico's national territory
U.S. payment
$15,000,000

What happened

A boundary dispute over whether Texas's border with Mexico lay at the Rio Grande or the Nueces River, combined with U.S. president James Polk's expansionist ambitions, led the United States to declare war on Mexico on 13 May 1846 after skirmishes in the disputed territory. Nearly two years of fighting ended when the Treaty of Guadalupe Hidalgo was signed on 2 February 1848 at the city of that name, to which the Mexican government had fled as U.S. forces advanced. Under its terms, Mexico ceded about 55% of its territory, including present-day California, Nevada, Utah, New Mexico, most of Arizona and Colorado, and parts of Oklahoma, Kansas, and Wyoming, and relinquished all claims to Texas, recognizing the Rio Grande as the border. The United States paid Mexico $15 million and agreed to settle its own citizens' debt claims against the Mexican government; the U.S. Senate ratified the treaty 34 to 14 on 10 March 1848, but deleted the article guaranteeing protection of existing Mexican land grants.

Why it matters

The treaty is the single largest territorial loss in Mexico's history, cutting the nation to less than half the size it had been at independence in 1821, and the Senate's removal of the land-grant protections left many Mexican landowners in the ceded territory without secure title under the new U.S. jurisdiction, a grievance that outlived the war by generations.

How we know

The treaty text survives in full at the U.S. National Archives, and the Senate's ratification vote and its amendment removing Article X are recorded in the congressional record.

Sources

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