The Mexican-American War finally made the United States a nation that stretched from sea to shining sea. This opened up the west even more to overland travelers, like emigrants and prospectors on the California Trail.

Find out more about how this battle and its fallout affected the expansion of our nation.

United States Vs. Mexico – 1846 To 1848

The Mexican-American war was the first US armed conflict chiefly fought on foreign soil. It started on Apr. 25, 1846, as a border skirmish between a newly independent Texas and Mexico. It ended with Mexico losing about a third of its territory, including present-day California, Utah, Nevada, Arizona, and New Mexico.

The war officially ended on Feb. 2, 1848, with the signing of the Treaty of Guadalupe Hidalgo.

A Timeline Of The Mexican-American War

  • Apr. 25, 1846 – The Mexican-American War begins.
  • May 8, 1846 – Battle of Palo Alto: The first official battle of the war.
  • May 9, 1846 – Battle at Resaca de la Palma.
  • May 13, 1846 – Congress officially declares war on Mexico.
  • June 1846 – Mexican politician Mariano Guadalupe Vallejo is arrested in the Bear Flag revolt in California.
  • Jul. 7, 1846 – Battle of Monterey.
  • Aug. 14, 1846 – Colonel Stephen Watts Kearney takes possession of Santa Fe.
  • January 1847 – The Californians surrender.
  • Feb 22-3, 1847 – Battle at Buena Vista.
  • April 19-20, 1847 – Battle of Cerro Gordo.
  • Sept. 12-14, 1847 – Battle of Mexico City.
  • Feb. 2, 1848 – The Treaty of Guadalupe Hidalgo is ratified by the US.

Fulfilling Our “Manifest Destiny”

James K. Polk had his eyes on California, New Mexico, and the Southwest. He believed the United States had a “manifest destiny” to spread across the continent to the Pacific Ocean. When his attempts to buy the land were rejected, Polk moved troops into the disputed areas between the Nuances and Rio Grande rivers, sparking conflict and eventually battle.

The Mexican-American War & California Trail History

On Jan. 24, 1848, just weeks before the official end of the Mexican-American War, gold was discovered at Sutter’s Mill in Coloma, California, by James W. Marshall. This marked the start of the California gold rush and the movement of close to 300,000 gold-seekers West, many along the California Trail.

  • John C. Frémont, aka “the Pathfinder,” fought in the Mexican-American War as part of the Topographical Corps of the US Army. He mapped out much of the California and Oregon Trails.
  • On Jul. 20, 1948, the Mormon Battalion, a volunteer unit of over 500 men, left their travels on the Mormon Trail west to fight in the Mexican-American War.
  • In October 1846, a banished member of the Donner-Reed party, James F. Reed, pleaded with John C. Frémont to send men to rescue his friends and family in return for his service in the Mexican-American War.

Learn More About The US Expansion West

Stop by the California Trail Interpretive Center in Elko, NV, to learn even more about the westward expansion of the United States and the events that fueled it, like the Mexican-American War.

Contact us today to plan your trip and get the latest information on upcoming exhibits and activities.

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