Lyman Run, located in Potter County, Pennsylvania, is a state-regulated recreational dam completed in 2007. Standing at a height of 52.6 feet and with a storage capacity of 1350 acre-feet, this earth dam serves primarily for recreational purposes in the West Branch Township. The dam, with a spillway width of 896 feet and a surface area of 40 acres, has a high hazard potential but is currently assessed to be in satisfactory condition.

Managed by the Pennsylvania Department of Environmental Protection, Lyman Run offers a serene setting for outdoor enthusiasts to enjoy activities such as fishing, boating, and hiking. The dam, with its uncontrolled spillway, plays a crucial role in regulating the downstream flow of Lyman Run, a tributary in the Buffalo District. Despite its moderate risk assessment, the dam has undergone regular inspections and meets state regulatory guidelines for operation and maintenance. With its picturesque surroundings and important recreational function, Lyman Run serves as a vital water resource and climate feature for the local community and visitors alike.