Naval Air Station Joint Reserve Base Willow Grove or NASJRB Willow Grove was a Naval Air Station owned by the U.S. Navy and located in Horsham Township, Montgomery County, Pennsylvania, United States four miles (6 km) northwest of the central business district of Willow Grove, which is north of Philadelphia. The installation was transferred to the Pennsylvania Air National Guard and the name changed to the Horsham Air Guard Station after the U.S. Navy departed in 2011.

Horsham Township is a home rule municipality in Montgomery County, Pennsylvania. It is located ten miles north of Center City Philadelphia. The township, incorporated in 1717, is one of the oldest original municipalities in Montgomery County. Although it retains the word "Township" in its official name, it has been governed by a Home Rule Charter since 1975 and is therefore not subject to the Pennsylvania Township Code. The population was 26,564 at the time of the 2020 census.