Lock Haven is a city in the U.S. state of Pennsylvania and serves as the county seat of Clinton County. It sits near the confluence of the West Branch Susquehanna River and Bald Eagle Creek, positioning it within the Pennsylvania Wilds region. The municipality functions as the principal city of the Lock Haven Micropolitan Statistical Area, which is part of the larger Williamsport–Lock Haven combined statistical area.

The site was long favored by pre-Columbian peoples before European contact in the 1500s. Cleary Campbell built the first log cabin in 1769, followed by Reed's Fort in 1773. Jeremiah Church laid out the town in 1833 as a timber hub and haven for travelers on the river and West Branch Canal. It became a borough in 1840 and a city in 1870, growing through resource extraction and transportation infrastructure.

The city features three National Register of Historic Places sites: the Memorial Park Site, Heisey House, and the Water Street District. The area contains Victorian-era museums and a mix of 19th- and 20th-century architecture. Gothic Revival, Greek Revival, and Italianate mansions from the railroad boom era remain prominent. A levee completed in 1995 protects the city from flooding that previously damaged local industry.

Visitors can explore the Piper Aviation Museum, which houses exhibits on the Piper Aircraft company and a collection of planes on the former factory grounds. The city offers cultural venues like Avenue 209 Coffee House for live music and open mic nights. Dining options include Texas Hotdogs and pizza from Checkers, while entertainment is available at Uncle Albert's tavern or Hangar 9.

The population was 8,108 as of the 2020 census. About a third of the workforce is employed in education, health care, or social services, though industry remains important. Access is provided via Interstate 80 and U.S. Route 220. The city is located within the Pennsylvania Wilds, offering nearby access to beautiful fall foliage, high mountain peaks, and Amish farm country.