The following are California State Volunteer Units that were active between 1861–1866 serving in the Union Army, most west of the Rocky Mountains in place of Federal troops: In 1861 four infantry regiments were recruited in Pennsylvania by Oregon Senator Edward D. Baker.
Though made up of Pennsylvanians they were attributed to California.
After the Battle of Ball's Bluff in October 1861 the brigade was renamed Philadelphia Brigade and the regiments were attributed to Pennsylvania as well.