The Treaty of Guadalupe Hidalgo Ends the Mexican-American War (March 10, 1848 – Ratification)

Background

The Mexican-American War (1846-1848) stemmed from territorial disputes between the United States and Mexico. After Texas gained independence from Mexico in 1836 and later joined the U.S. in 1845, tensions escalated. The U.S., under President James K. Polk, was pursuing Manifest Destiny, aiming to expand westward.

After two years of fighting, U.S. troops, led by General Winfield Scott, captured Mexico City in September 1847, forcing Mexico to negotiate.

What Happened?

On March 10, 1848, the U.S. Senate ratified the Treaty of Guadalupe Hidalgo, officially ending the war.

Key terms of the treaty included:

• Mexico ceded over 500,000 square miles of territory to the U.S., including California, Nevada, Utah, Arizona, and parts of New Mexico, Colorado, and Wyoming.
• The Rio Grande was established as the U.S.-Mexico border.
• The U.S. paid Mexico $15 million for the acquired lands.
• The U.S. assumed $3.25 million in debts owed by Mexico to American citizens.

Impact for the Future

This treaty reshaped the map of North America and was one of the largest territorial expansions in U.S. history. The new territories would later fuel tensions over slavery, leading to conflicts such as the Civil War (1861-1865). The war also deepened Mexican resentment toward the U.S., affecting diplomatic relations for decades.