As Civil War hostilities rapidly escalated in July 1861—and United States Army personnel stationed in California left for eastern battlefronts—President Lincoln’s cabinet raised an important issue: How was the Union to protect and preserve its states and territories in the trans-Mississippi west?
The overland trails, as well as the Overland Mail routes between the Carson Valley in Nevada, Salt Lake City in Utah, and Fort Laramie in Wyoming, must be kept open. Pacific seaports needed protection. Economic factors were crucial: should the Confederacy gain control of California’s gold, Colorado’s gold, and Nevada’s silver-rich Comstock Lode, the loss of these assets could very well spell defeat for the Union.
Another worry was the potential danger in Southern California, where a number of influential men were avid Secessionists. Realizing that volunteer soldiers were desperately needed, Congress passed the Voluntary Employment Act, requesting each western state to raise a force to guard the home front. This appeal had barely circulated before a new threat materialized, the Confederate invasion of New Mexico Territory (which included modern Arizona) on July 23, 1861. As everyone recognized, Confederate possession of that region could lead to the seizure of all the American Southwest.
Over the war’s duration volunteers from California, some 17,000 in all, joined the Union’s cause. They prevented an insurrection at Los Angeles, reclaimed New Mexico Territory, and safeguarded the Overland Mail routes, the emigrant trails, and coastal seaports—insuring that the U.S. economy didn’t lose its valuable mineral assets. California volunteers helped preserve the West for the Union, often enduring great hardships, while federal troops concentrated on winning the War in the eastern and southern states.