The California campaign, 1849-1851.
The Battle of San Fernando was an engagement of the Rocky Mountain War that took place in San Fernando, California from 5-7 July 1850. The battle pitted the California Guard led by General Francisco Hernandez against a large C.N.A. force led by General David Homer.
General Homer's force had departed from Fort Webster, Vandalia in March 1849, and the Mexicans initially assumed its target was Conyers, Mexico del Norte. Instead, Homer's men continued west, reaching Mendoza, Arizona in October. The following spring, Homer's men resumed their march west, passing through Williams Pass in June 1850. Meanwhile, General Hernandez' force were waiting in the foothills west of the pass.
The two armies met at San Fernando in the last field battle of the war on 5 July 1850. Over the next three days, the two armies fought to a draw, and both retreated from the battlefield, Hernandez having lost 4,500 men, and Homer over 5,400. The North Americans retreated back to Williams Pass, while the Mexicans were able to regroup and persue them. The arrival of additional forces from the U.S.M. and the C.N.A. in the fall of 1850 set the stage for the First Battle of Williams Pass.
Sobel's source for the Battle of San Fernando is volume 10 of the C.N.A.'s official history of the Rocky Mountain War.