The 109th Infantry Regiment is a parent infantry regiment of the United States Army, represented in the Pennsylvania Army National Guard by the 1st Battalion, 109th Infantry, part of the 2nd Brigade Combat Team, 28th Infantry Division.

The Pennsylvania Army National Guard, abbreviated PAARNG, is part of the United States Army National Guard and is based in the U.S. Commonwealth of Pennsylvania. Together with the Pennsylvania Air National Guard, it is directed by the Pennsylvania Department of Military and Veterans Affairs. The PAARNG maintains 124 armories and is present in 87 communities across the Commonwealth.