The vast majority of Pennsylvania soldiers fought in the Eastern Theater, with only about 10% serving elsewhere. The thirteen regiments of the Pennsylvania Reserves fought as the only army division all from a single state, and saw action in most of the major campaigns and battles of the Army of the Potomac. The Philadelphia Brigade was also a rarity, in that all of its regiments were recruited from a single city. In an unusual circumstance, the Philadelphia Corn Exchange sponsored and paid for a regiment, the 118th, which became known as the "Corn Exchange Regiment."