The Battle of La Mesa of the Mexican-American War occurred on January 9, 1847, in present-day Vernon, California, the day after the Battle of Rio San Gabriel during the California Campaign.
After crossing the river, the American troops advanced to meet Flores' 300-strong force of Californio militia near a ravine where the city of Vernon now stands.
The Battle of La Mesa occurred on January 9, 1847 in present-day Vernon, the day after the more-decisive Battle of Rio San Gabriel. At La Mesa, the outgunned and outnumbered Californios were quickly defeated by a force commanded by Commodore Robert F. Stockton. Stockton's force was largely on foot, but had rifles, while the Californios fought on horseback with only lances. In the battle, the Californios suffered 15 dead and 25 wounded. After a day of charging and outflanking the American soldiers, the Californios fell back in exhaustion and camped at present-day Pasadena, ceding Los Angeles to Stockton's forces.
This battle was the last armed resistance to American domination of California and General Flores fled back to Mexico. The issue of California was settled with the signing of the Treaty of Cahuenga by Lieutenant-Colonel (later Major General) John C. Frémont and General Andres Pico on January 13, 1847.