Answer:
Under the Treaty of Guadalupe Hidalgo, which settled the Mexican-American War, the United States gained more than 500,000 square miles (1,300,000 square km) of land, expanding U.S. territory by about one-third. Mexico ceded nearly all the territory now included in the U.S. states of New Mexico, Utah, Nevada, Arizona, California, Texas, and western Colorado for $15 million and U.S. assumption of its citizens' claims against Mexico.