Conquest of California
The Conquest of California by the United States from Mexico in 1846 was one of the first decisive triumphs of the Mexican-American War. It was marked by a series of very small battles.
When war was declared on May 13, 1846 between the United States and Mexico, it took almost two months (mid-July 1846) for definite word of war to get to California. U.S. consul Thomas O. Larkin, stationed in Monterey, on hearing rumors of war tried to keep peace between the Americans and the small Mexican military garrison commanded by José Castro. American army captain John C. Frémont with about 60 well-armed men had entered California in December 1845 and was making a slow march to Oregon when they received word that war between Mexico and the U.S. was imminent.
On June 15, 1846, some 30 settlers, mostly Americans, staged a revolt and seized the small Mexican garrison in Sonoma. They made up a flag and raised the "Bear Flag" over Sonoma. Days later the U.S. Army, led by Fremont, took over on June 23. The California state flag today is based on this original Bear Flag, and continues to contain the words "California Republic."
Commodore John Drake Sloat, on hearing of imminent war and the revolt in Sonoma, ordered his naval forces to occupy Yerba Buena (present San Francisco) on July 7 and raise the American flag. On July 15, Sloat transferred his command to Commodore Robert F. Stockton, a much more aggressive leader. Commodore Stockton put Frémont's forces under his orders. On July 19th, Frémont's "California Battalion" swelled to about 160 additional men from newly arrived settlers near Sacramento, and he entered Monterey in a joint operation with some of Stockton's sailors and marines. The official word had been received -- the Mexican-American War was on. The American forces easily took over the north of California; within days they controlled San Francisco, Sonoma, and Sutter's Fort in Sacramento.
In Southern California, Mexican General José Castro and Governor Pío Pico fled from Los Angeles. When Stockton's forces entered Los Angeles unresisted on August 13, 1846, the nearly bloodless conquest of California seemed complete. Stockton, however, left too small a force (36 men) in Los Angeles, and the local Hispanics (called "Californios"), acting on their own and without help from Mexico, led by José Mariá Flores, forced the small American garrison to retire in late September. 200 Reinforcements sent by Stockton, led by US Navy Captain William Mervine were repulsed in the Battle of Dominguez Rancho on October 7-9, near San Pedro, where 14 U.S. Marines were killed. Meanwhile, General Kearny with a much reduced squadron of 100 dragoons finally reached California after a grueling march across New Mexico, Arizona and the Sonora desert. On December 6, 1846, They fought the Battle of San Pasqual near San Diego, California, where 18 of Kearny's troop were killed--the largest American casualties lost in battle in California.
Stockton rescued Kearny's surrounded forces and with their combined force, they moved northward from San Diego, entering the Los Angeles area on January 8, 1847, linking up with Frémont's men and with American forces totaling 660 troops, they fought the Californios in the Battle of Rio San Gabriel and the next day they fought the Battle of La Mesa. The last significant body of Californios surrendered to American forces three days later, marking the end of the war in California. On January 13, 1847, the "Treaty of Cahuenga" was signed; it was not a real treaty but merely an agreement to recognize American control of the local area..
On in late January, 1847, Army lieutenant William Tecumseh Sherman and his soldiers arrived in Monterey, as American forces in the pipeline continued to stream into California. In mid-March, the Seventh Regiment of New York Volunteers of about 900 men start arriving in California. All of these men were in place when gold was discovered in January 1848.
The Treaty of Guadalupe Hidalgo, signed in February, 1848, marked the end of the Mexican-American War. In that treaty, the United States agreed to pay Mexico $18,250,000; Mexico formally ceded California (and other northern territories) to the United States, and a new international boundary was drawn; San Diego Bay is one of the only natural harbors in California south of San Francisco, and to claim all this strategic water, the border was slanted to include it.
- Hubert Howe Bancroft. The Works of Hubert Howe Bancroft, vol 22, History of California 1846-48; complete text online; famous, highly detailed narrative written in 1880s