Cruise the scenic Iron Mountain Road, a 17-mile adventure connecting Custer State Park to Mount Rushmore. Prepare for twists and turns with breathtaking Black Hills views. Keep an eye out for the Doane Robinson and Scovel Johnson tunnels. Time your drive to see Mount Rushmore framed perfectly through the openings! Pigtail Bridges: These ingenious structures loop the road back under itself, allowing for steeper climbs and showcasing engineering marvels.