The treaty that ended the Mexican-American War and ceded California to the United States was the Treaty of Guadalupe Hidalgo, signed on February 2, 1848. This treaty marked the conclusion of the war between the U.S. and Mexico, which had been fought from 1846 to 1848 over territorial disputes, particularly in Texas and the lands that are now the southwestern United States.
Under the Treaty of Guadalupe Hidalgo, Mexico agreed to cede a vast amount of territory to the United States, which included not only present-day California but also modern-day Nevada, Utah, Arizona, New Mexico, and parts of Colorado and Wyoming. In total, Mexico surrendered approximately 525,000 square miles of land, about half of its territory, to the U.S.
In return for the land, the United States agreed to pay Mexico $15 million and assumed about $3.25 million in debts owed by Mexico to U.S. citizens. The treaty also included provisions that guaranteed the property rights of Mexican citizens living in the newly acquired territories and promised that they would be granted U.S. citizenship. However, many of these provisions were not fully respected in the years that followed.
The signing of the Treaty of Guadalupe Hidalgo was a pivotal moment in the history of both nations. For the United States, it represented a major step toward the fulfillment of Manifest Destiny, the belief that the U.S. was destined to expand across the North American continent. For Mexico, it was a devastating loss of land and national pride.
California, one of the territories gained through the treaty, quickly became one of the most valuable regions for the U.S., especially after the discovery of gold at Sutter’s Mill in 1848, just months after the treaty was signed. This sparked the California Gold Rush, which brought a massive influx of settlers to the region and accelerated California’s path to statehood in 1850.
Thus, the Treaty of Guadalupe Hidalgo not only ended the Mexican-American War but also reshaped the borders and the future of both Mexico and the United States, with California becoming a key part of the new American West.
