[2] It is part of the Johnstown, Pennsylvania, Metropolitan Statistical Area.

The township was named for Jeremiah Sullivan Black, a native of Somerset County who became Chief Justice of the Supreme Court of Pennsylvania, U.S. Attorney General, and U.S Secretary of State.

[3] According to the United States Census Bureau, the township has a total area of 42.5 square miles (110 km2), of which 42.5 square miles (110 km2) is land and 0.02% is water.

Rockwood sits at the confluence of Coxes Creek and the Casselman River, between Milford Township to the northwest and Black Township to the southeast.

[4] At the 2000 census there were 980 people, 364 households, and 281 families living in the township.