Gilpin's Hydrographic Map of North America, 1848

Lasting Consequences

The territories of the Mexican Cession eventually formed part or all of New Mexico, Arizona, California, Colorado, Utah, Nevada, and Wyoming. Soon after the war, the discovery of gold in California and the large migration of Anglo-Americans and other fortune seekers transformed the region. Mexican-American Californios became a minority group in just one year. Throughout the new U.S. Southwest, Mexican Americans faced racism and the loss of their land titles. The Republic of Mexico had to accept the new role of a diminished nation, having lost half of its land and its control of the rivers that flowed into northern Mexico.

The U.S. conquest of Mexican territory heightened tensions between the North and South over expanding slavery. Bloodshed in Kansas, at the center of this map, followed just a few years later.