Sharpsburg is a borough in Allegheny County, Pennsylvania, United States, 5 miles northeast of downtown Pittsburgh, along the Allegheny River. In 1900, nearly 7,000 people lived here; in 1920, the population peaked at just over 8,900 people. The population was 3,187 at the 2020 census. In the past, it had a rolling mill, foundries, machine shops, and manufacturers of varnish, brick, glass, lumber products, wire, hair, felt, and lubricating oil. In January 1869, the H. J. Heinz Company was founded in Sharpsburg as Heinz Noble& Company to manufacture and sell bricks.