Leechburg is a borough in southern Armstrong County in the U.S. state of Pennsylvania, 35 miles northeast of Pittsburgh. A population of 2,149 residents live within the borough limits as of the 2020 census, according to United States Census Bureau. Leechburg was founded by David Leech, for whom it was named, and was incorporated as a borough in 1850. Located along the Kiskiminetas River, Leechburg was a major port of the Pennsylvania Canal.