Granite Spires on the Needles Highway, Custer State Park

The Needles Highway winds through Custer State Park in South Dakota's Black Hills, threading past granite formations carved by frost and erosion over roughly a billion years. The road, designated South Dakota Highway 87, was completed in 1922 under the direction of Governor Peter Norbeck, who laid out the route on foot and horseback to highlight the spires rather than bypass them. Its narrow tunnels and tight turns were built specifically to frame these rock towers, some of which climb over 30 feet above the surrounding pine and aspen forest. The granite dates to the Precambrian era, among the oldest exposed rock in the region, and the needle-like spires form as softer material erodes away, leaving harder mineral veins standing exposed.