Lock Haven is a city in Clinton County, Pennsylvania, United States. It is located along the west branch of the Susquehanna River and is the county seat of Clinton County. The city has a population of approximately 9,700 people as of the 2010 census. Lock Haven is known for its scenic beauty, outdoor recreational activities, and its historic downtown area. It is home to Lock Haven University, a public university offering various undergraduate and graduate programs. The city also hosts the annual Pennsylvania State Flaming Foliage Festival, which attracts thousands of visitors each year.