Glenside is a census-designated place located in Cheltenham Township and Abington Township in Montgomery County, Pennsylvania, United States. It borders Northwest Philadelphia. The population was 7,737 at the 2020 census on a land area of 1.3 square miles. Glenside is most notable for its entertainment, including Keswick Theatre, restaurants, recreational facilities, and parks. Glenside station is one of the busiest in the SEPTA system.