History of U.S. land acquisitions Between 1803 and 1917, the United States acquired more than 1,388,000,000 acres (2,168,750 square miles, or about 5,617,000 square km) of land. The land acquired through the Mexican Cession is in the southwest (Treaty of Guadalupe Hidalgo). (more) Mexican Cession Mexico-United States [1848] Written by Sanat Pai Raikar Sanat Pai Raikar is a quizmaster and writer based out of Bangalore, India. His first quiz book, Three's A Quiz, was written from memory. Sanat has cofounded Quizarre, which provides quiz, crossword,... Sanat Pai Raikar Fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors Last updated Apr. 10, 2026 •History Mexican Cession, relinquishment of more than half of Mexico’s territory to the United States under the terms of the Treaty of Guadalupe Hidalgo, which ended the Mexican-American War in 1848. The ceded territory covered more than 525,000 square miles (1,360,000 square km), including land that is now part of the U.S. states of New Mexico, Utah, Nevada, Arizona, California, Texas, Wyoming, Oklahoma, Kansas, and Colorado. Though annexed through war, the U.S. paid Mexico $15 million...

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