This project is used to relate all units from California who served in the Union Army.
California's involvement in the American Civil War included sending gold east, recruiting volunteer combat units to replace regular forces in territories of the Western United States, maintaining and building numerous camps and fortifications, suppressing secessionist activity and securing the New Mexico Territory against the Confederacy. The State of California did not send its units east, but many citizens traveled east and joined the Union Army there, some of whom became famous. California's Volunteers also conducted many operations against the native peoples within the state and in the other Western territories of the Departments of the Pacific and New Mexico.
Following the Gold Rush California was settled primarily by Midwestern and Southern farmers, miners and businessmen. Democrats dominated the state from its foundation. Southern Democrats sympathetic to secession, although a minority in the state, were a majority in Southern California and Tulare County, and were in large numbers in San Joaquin, Santa Clara, Monterey, and San Francisco counties. California was home for powerful businessmen who played a significant role in Californian politics through their control of mines, shipping, finance, and the Republican Party but were a minority party until the secession crisis.
In 1860, as tensions escalated in the East, pro-Union Californians protested the perceived pro-Southern bias of the San Francisco Roman Catholic archdiocese's weekly newspaper, The Monitor, by dumping its presses into San Francisco Bay. In the beginning of 1861, as the secession crisis began, the secessionists in San Francisco made an attempt to separate the state and Oregon from the union, which failed. Southern California, with a majority of discontented Californios and Southern secessionists, had already voted for a separate Territorial government and formed militia units, but were kept from secession after Fort Sumter and by Federal troops drawn from the frontier forts of the District of Oregon, and District of California (primarily Fort Tejon and Fort Mojave).
Patriotic fervor swept California after the attack on Fort Sumter, providing the manpower for Volunteer Regiments recruited mainly from the pro-Union counties in the north of the State. When the Democratic party split over the war, Republican supporters of Lincoln took control of the state in the September elections. Volunteer Regiments were sent to occupy pro-secessionist Southern California and Tulare County, leaving them generally powerless during the war itself. However some Southerners traveled east to join the Confederate Army, evading Union patrols and hostile Apache. Others remaining in the state attempted to outfit a privateer to prey on coastal shipping, and late in the war two groups of partisan rangers were formed but none were successful.