The Mexican–American War was a conflict between the United States and Mexico that began in April 1846 and ended with the signing of the Treaty of Guadalupe Hidalgo in February 1848. The war was fought mainly in what is now the southwestern United States and Mexico, and resulted in a victory for the United States. Under the treaty, Mexico ceded around half of its territory, including present-day California, New Mexico, Arizona, and parts of Colorado, Nevada, and Utah, to the United States.