Black Hills, South Dakota - Custer State Park - Needles Eye Tunnel (2019)

South Dakota Highway 87 (SD 87) is a 37.894-mile-long (60.984 km) state highway in the southwestern part of the U.S. state of South Dakota. It travels through the Black Hills region. The highway's southern terminus is at an intersection with U.S. Route 385 (US 385), about 6 miles (9.7 km) southeast of Pringle, within the southwestern part of Wind Cave National Park. Its northern terminus is at an intersection with US 16/US 385 about 3 miles (4.8 km) south-southwest of Hill City, within the east-central part of the Black Hills National Forest.

The highway travels through Wind Cave National Park and Custer State Park. The northern 14 miles (23 km) of the highway is also known as the Needles Highway. The Needles Highway, along with the concurrency with US 16A, are also part of the Peter Norbeck Scenic Byway. Portions of the highway are also a section of Custer State Park's Wildlife Loop.

After splitting from US 16A, the route is known as the Needles Highway. This segment is 14 miles (23 km) long. Finished in 1922, the highway is named after the high granite "needles" it winds among. Access to the Needles Highway requires a Custer State Park entrance license, making that portion of SD 87 a toll road. Along this stretch lies the Black Hills Playhouse. The highway passes through two tunnels blasted through sheer granite walls—Iron Creek Tunnel and Needles Eye Tunnel. Owing to the narrow roadway, sharp turns, and low tunnels, the road has very little traffic. The vehicles that do travel this road are almost exclusively sightseers.

Just after Needles Eye Tunnel, Highway 87 serves as the northern terminus of SD 89. After this junction, SD 87 has one more tunnel, Hood Tunnel. It then provides access to the Sylvan Lake Resort. The route finally ends at US 16/385 south of Hill City.