U.S. Route 16A The route passes through Keystone, South Dakota; Mount Rushmore National Memorial; The Norbeck Wildlife Management Area and Black Elk Wilderness within the Black Hills National Forest; and Custer State Park (including State Game Lodge and Legion Lake); before rejoining the parent highway. US 16A is famous for its scenic, one-lane tunnels aligned to frame the faces on Mount Rushmore, its "pigtail bridges", and its sections of divided highway but with single (and narrow) lanes on each roadway. It is the only route which can be used to drive through Custer State Park without having to pay an entrance fee for
Mount Sugarloaf State Reservation Mount Sugarloaf State Reservation Mount Sugarloaf State Reservation is a state-owned, public recreation area managed by the Massachusetts Department of Conservation and Recreation located in South Deerfield, just west of the Connecticut River. The state park includes the summits of North Sugarloaf Mountain and South Sugarloaf Mountain, as well as 1.75 miles of frontage on the Connecticut River and two river islands. The park is part of a larger park designation called the Connecticut River Greenway State Park. Portions of the park property along the river are used by the University of Massachusetts Amherst for agricultural research. The state maintains