Willow Grove is a census-designated place (CDP) in Montgomery County, Pennsylvania, United States. A community in Philadelphia's northern suburbs, the population was 13,730 at the 2020 census. It is located in Upper Dublin Township, Abington Township and Upper Moreland Township. Willow Grove was once known for Willow Grove Park, an amusement park that was open from 1896 to 1976, now the site of Willow Grove Park Mall. Willow Grove is considered an edge city of Philadelphia, with large amounts of retail and office space.

Montgomery County, colloquially referred to as Montco, is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population of the county was 856,553, making it the third-most populous county in Pennsylvania after Philadelphia and Allegheny counties. The county is part of the Southeast Pennsylvania region of the state.