Biddle Air National Guard Base, located in Horsham Township, Montgomery County, Pennsylvania, United States, is an operational military installation. It is owned by the Department of Defense and operated by the US Air Force, with control exercised by the Pennsylvania Air National Guard. The base was established in 1928 by Pitcairn Aircraft Company as Pitcairn Field No. 2. It was subsequently known as Horsham Air Guard Station from 2011 to 2021 before being renamed in honor of Charles Biddle, who founded the Pennsylvania Air National Guard's 103rd Observation Squadron, now designated as the 103rd Attack Squadron. The site previously served as Naval Air Station Joint Reserve Base Willow Grove. Biddle Air National Guard Base functions as a host for various Army National Guard Units and other government agencies. The primary host unit stationed at the base is the 111th Attack Wing. Other units present include Detachment 1, 201st RED HORSE Squadron; 270th Engineering Installation Squadron; 56th Stryker Brigade Combat Team; 316th Sustainment Command (Expeditionary); 412th Engineer Command; 3rd Medical Command; and 11th Aviation Command.