Sharpsburg is a borough in Allegheny County, Pennsylvania, 5 miles (8 km) northeast of Pittsburgh, along the Allegheny River. 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 1900, 6,842 people lived here; by 1940, 8,202 people lived in Sharpsburg.