1848 treaty to end the Mexican-American War, named after the town of Guadalupe Hidalgo. As a result of this treaty, the United States gained substantial territories, through the annexation of Texas and the purchase of New Mexico, Arizona, California, and parts of other southwestern states.

This treaty proved to be a source of some contention in the US Chicano movement of the 1970s, brought to the forefront by people who claimed that the US did not hold to the conditions of the treaty, which required the US to grant equal rights to any Mexican peoples who chose to remain within US borders after it was signed.