Press Release

167 Years Ago the U.S. and Mexico Signed the Treaty of Guadalupe Hidalgo

Denver -  Before there was a Colorado, southern and western Colorado were once part of Spain, then Mexico. This changed on February 2, 1848, when the United States and Mexico signed the Treaty of Guadalupe Hidalgo, ending the two-year-long Mexican-American War. In exchange for peace, Mexico ceded nearly 950,000 square miles – almost half of its territory – to the United States. The U.S. also paid Mexico $15 million to compensate for damages to land and property caused by the war.

This territory became what we now know as the American Southwest. Mexican land was eventually divided into all or part of Colorado, New Mexico, California, Arizona, Nevada, Utah, and Wyoming.

Nearly 80,000 Mexican citizens lived in this area, and the Treaty of Guadalupe Hidalgo promised to protect them. However, Congress refused to ratify or weakened parts of the treaty that guaranteed the property and civil rights of former Mexican citizens.

Land was the biggest issue. Many Hispanics living in what is now northern New Mexico and southern Colorado lived on communal land grants given to them by Spain, Mexico, or the governor of New Mexico. These grants included individual plots for families, but also communal grazing, hunting, and gathering lands. Spanish and Mexican land law allowed for these communal uses, but American land law did not. Many land grants were broken up in the late nineteenth century. Communal lands were lost, impoverishing the communities and families that depended on them.

In the 1960s and 1970s, Chicano activists in New Mexico and southern Colorado fought for access to these communal lands and restore the land grants. In Colorado, activists in the San Luis Valley successfully regained access to some communal lands in 2002. History Colorado’s El Movimiento: The Chicano Movement in Coloradoexhibit, which opens February 7, features more about land rights.

History Colorado, a Smithsonian Affiliate, inspires generations to find wonder and meaning in our past and to engage in building a better Colorado. Find us on and on Twitter@HistoryColorado. For more information visit, call 303-HISTORY (447-8679) or visit us at the History Colorado Center at 1200 Broadway, Denver, CO 80203.


History Colorado's mission is to inspire generations to find wonder and meaning in our past and to engage in creating a better Colorado. We serve as the state's memory, preserving the places, stories, and material culture of Colorado through our museums, educational programs, historic preservation grants, research library, collections, and outreach to Colorado communities. Find History Colorado on all major social media platforms. Visit or call (303) HISTORY for more information.