Harrisburg is the capital of the Commonwealth of Pennsylvania, a state of the Unite States of America. As of the 2000 census, the city had a population of 48,950. The Harrisburg area population was estimated in 2006 at 652,263, making it the fourth most populous metropolitan area in Pennsylvania, after Philadelphia, Pittsburgh and Allentown-Bethlehem-Easton (The Lehigh Valley). Harrisburg is the county seat of Dauphin County and lies on the east bank of the Susquehanna River, 105 miles (169 km) west-northwest of Philadelphia.