Willow Grove is a census-designated place (CDP) in Montgomery County, Pennsylvania. A community in Philadelphia's northern suburbs, the population was 15,726 at the 2010 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. Naval Air Station Joint Reserve Base Willow Grove is located northwest of the Willow Grove CDP in Horsham Township. NAS JRB Willow Grove will continue operating through 2010, and closure will occur by September 2011. China Airlines operates the Philadelphia Mini Office in Building 39G at 2300 Computer Avenue in the Willow Grove CDP and in Upper Moreland Township.