city, seat (1839) of Clinton county, north-central Pennsylvania, U.S. It lies along the West Branch Susquehanna River (a major tributary of the Susquehanna (Susquehanna River)), on the southern slope of Bald Eagle Mountain, 26 miles (42 km) southwest of Williamsport. Founded in 1834 by Jeremiah Church, a land speculator, it was laid out on the site of the frontier post, Fort Reed, and developed as a lumbering centre. Incorporated as a borough in 1840 and as a city in 1870, it was named for the Pennsylvania Canal lock and the huge lumber boom that made it a “haven” for lumberjacks from nearby logging camps.

The city's manufactures include automotive parts, paper, and textiles. Lock Haven University of Pennsylvania (Pennsylvania, University of) was founded in 1870. The Piper Aviation Museum is located in the former Piper Aircraft engineering building in Lock Haven. Kettle Creek and Bald Eagle State parks and the Bucktail Natural Area are nearby. Pop. (1990) 9,230; (2000) 9,149.