Cook Forest State Park is a 8,500-acre (3,440 ha) Pennsylvania state park in Farmington Township, Clarion County, Barnett Township, Forest County and Barnett Township, Jefferson County, Pennsylvania in the United States. Located just south of the Allegheny National Forest, the park is a heavily wooded area of rolling hills and mountains along the Clarion River in northwestern Pennsylvania. Cook Forest State Park is known for some of America's finest virgin white pine and hemlock timber stands and was once called the "Black Forest" due to the preponderance of evergreen tree coverage.

Jefferson County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 44,492. Its county seat is Brookville. The county was established on March 26, 1804, from part of Lycoming County and later organized in 1830. It is named for President Thomas Jefferson. It is home to Punxsutawney Phil, the most famous groundhog that predicts when spring will come every February 2 on Groundhog Day. The county is part of the North Central Pennsylvania region of the state.