Lock Haven
- County:
- Clinton County
- County Seat:
- Yes
- Area (mi²):
- 2.496
- State:
- Pennsylvania
Lock Haven is a city located in Clinton County, Pennsylvania. Lock Haven has a 2026 population of 8,531. It is also the county seat of Clinton County. Lock Haven is currently declining at a rate of -0.09% annually but its population has increased by 5.4% since the most recent census, which recorded a population of 8,094 in 2020.