Newtown Square, Pennsylvania is a borough in Bucks County, Pennsylvania, United States. The population was 2,248 at the 2010 census. It is located just west of the Trenton, New Jersey metropolitan area, and is part of the larger Philadelphia metropolitan area. It is entirely surrounded by Newtown Township, from which it separated in 1838. State Street is the main commercial thoroughfare with wide sidewalks, shops, taverns, and restaurants.