Mapa de los Estados Unidos de Mejico [Map of the United States of Mexico] by J. Disturnell, 1847
Negotiators of the Treaty of Guadalupe Hidalgo agreed to use an 1847 map by J. Disturnell as the reference for the new boundary between the U.S. and Mexico. They found that the map had some serious errors, depicting El Paso and part of the Rio Grande many miles from their true locations, which complicated the negotiations.
Geography and Map Division, Library of Congress
The Treaty of Guadalupe Hidalgo
In March 1848 the U.S. Senate approved for ratification the treaty ending the Mexican War, which was signed in Guadalupe Hidalgo, Mexico, on February 2. In exchange for war-damage compensation of $15 million, Mexico ceded to the U.S. more than half its territory. The treaty redefined the U.S.-Mexico border and extended U.S. territory to the Pacific coast, intensifying congressional debates about the westward extension of slavery. Though the treaty protected the rights of former Mexican nationals who resided in the territory, many lost their land.