[6] According to the United States Census Bureau, the borough has a total area of 1.6 square miles (4.1 km2), all land.

These municipalities, along with East Pittsburgh, Edgewood, Rankin, Swissvale, and Turtle Creek, make up the Woodland Hills School District.

Forest Hills is located along the Route 30 portion of the Lincoln Highway, which, along with Greensburg Pike, serves as a main artery of the borough.

Until 2015, near the eastern border with Chalfant, there once stood an historic, five-million-volt Van de Graaff generator and particle accelerator known as the Westinghouse Atom Smasher.

[16] However, the apparatus was torn down in 2015, when the property that had served as the primary campus of the Westinghouse Research Laboratories from 1916 to 1956[17] was being prepared for redevelopment.