[3] According to the United States Census Bureau, the township has a total area of 0.5 square miles (1.3 km2), all land.

[4] Baldwin Township has four borders, including the Pittsburgh neighborhoods of Brookline to the north and Overbrook to the northeast and southeast.

[5] The area was named for Henry Baldwin, a Pittsburgh lawyer who served as an Associate Justice of the United States Supreme Court from 1830 until his death in 1844.

Baldwin Township was originally 10,550 acres (42.7 km2) and consisted of the present-day Pittsburgh neighborhoods of Carrick, Hays, Brookline, and Overbrook, along with the present-day municipalities of Brentwood, Whitehall, Castle Shannon, and Baldwin Borough.

Due to the lack of maintenance throughout the township's roads, residents of many areas broke off to form their own municipalities.

From 1915 to 1951, approximately 8,700 acres (35 km2) of the original Baldwin Township broke off to become the municipalities of Brentwood, Castle Shannon, Mt.

Historians calculate that if Baldwin Township had never been divided, it would now be the second largest community in Allegheny County, with a population of over 100,000.

23.8% of all households were made up of individuals, and 9.9% had someone living alone who was 65 years of age or older.