Colonel Denning State Park, in north central Cumberland County, is in Doubling Gap, so named by the “S” turn where Blue Mountain doubles back on itself. This feature may be seen from the Doubling Gap Vista in adjacent Tuscarora State Forest. The park has 273 acres of woodland and a 3.5-acre lake.and Numerous picnic tables and charcoal grills are scattered throughout the park. There are two picnic pavilions that may be reserved up to 11 months in advance for a fee. Unreserved picnic pavilions are free on a first-come, first-served basis. Play equipment is near both picnic pavilions.