Tarentum is a borough in Allegheny County in the U.S. state of Pennsylvania. It is 22 miles northeast of Downtown Pittsburgh, along the Allegheny River. Tarentum was an industrial center where plate glass and bottles were manufactured; bricks, lumber, steel and iron novelties, steel billets and sheets, sack and wrapping paper were also produced. The Pennsylvania Railroad operated a station in Tarentum; its rail line ran through the town. The population was 4,352 at the 2020 census.