R. B. Winter State Park is a Pennsylvania state park on 695 acres (281 ha) in Hartley Township, Union County, Pennsylvania in the United States. It is in the Ridge and valley region of Pennsylvania and is surrounded by Bald Eagle State Forest. R. B. Winter State Park is in a shallow basin that is surrounded by ridges. Halfway Lake is the central recreational focus of the park. The park is 18 miles (29 km) west of Lewisburg on Pennsylvania Route 192.The park was originally called "Halfway Dam State Park", but was renamed "R.B. Winter State Park" on May 23, 1957 to honor state forester Raymond Burrows Winter, who was instrumental in establishing the park and had worked there and the surrounding state forest for 45 years.
R. B. Winter State Park has 6.3 miles (10 km) of hiking trails that meander around the park and along the lakeshore. The park is also a trailhead for the hiking, mountain biking and snow mobile trails in Bald Eagle State Forest. Most of the trails in the park are open to mountain biking except for Rapid Run Trail and Mid State Trail and part of Overlook Trail. R. B. Winter State Park is open to cross-country skiing and snowmobiling during the winter months.