Iron Mountain Road, South Dakota

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Iron Mountain Road

The scenic Iron Mountain Road winds its way through Black Hills National Forest and Custer State Park and past Mount Rushmore National Monument.

  • 16 miles long 
  • 45-60 minutes to travel 
  • Approximately 20 miles from Rapid City and 16 miles of Custer. 
  • The only road that travels through Custer State park free of charge. 
  • Pigtail bridges and winding single-lanes make this road fun as well as scenic.


Iron Mountain Road, also known as US-16A, begins just outside of Keystone, South Dakota. From Keystone, the scenic drive takes travelers past Mount Rushmore and to the top of Iron Mountain (where a pull-out provides an amazing vista of the Black Hills and Mount Rushmore) before winding back down toward Custer State Park and SD-36.

In addition to the spectacular views of Mt. Rushmore, curving single-lanes and unique pigtail bridges, Iron Mountain Road is the only road that passes through Custer State Park without a fee station.

Iron Mountain Road is not maintained during the winter, and the overview at the top of Iron Mountain is closed during winter months. Parts of the road are not recommended for RVs and large trailers.

Driving Directions

From Rapid City, take US-16W south 18 miles to the US-16 Alt E exit. Take US-16 Alt E approximately 2.5 miles to Keystone, where it becomes Iron Mountain Road. The southern end of Iron Mountain Road begins at the junction of US-16A and SD-36, 16 miles east of Custer.


It takes 45-60 minutes to travel the 16 miles of Iron Mountain Road.


  • Winds and climbs through the Black Hills, past Mount Rushmore and into Custer State Park.
  • Three corkscrew-shaped pigtail bridges wind down underneath themselves. 
  • Single-lane-tunnels were cut through granite in order to frame Mount Rushmore as drivers pass through. 
  • Wildlife, including mountain goats, elk, bison, bighorn sheep and turkey, abounds along Iron Mountain Road.