Why Go: The ruggedly beautiful topography of South Dakota’s Black Hills presented highway engineers with some unique challenges. They responded by constructing two “impossible” roads — the Needles Highway (Rte. 87) and Iron Mountain Road (Rte. 16A) — that thread their way through the mountains using steep grades, one-lane rock-walled tunnels, hairpin curves and photogenic spiral “pigtail” bridges. This ride, which traverses both (and swings by Mount Rushmore), is as beautiful as it is challenging, crossing wide-open meadows and deep canyons that are home to abundant wildlife including elk, bison, antelope, coyotes, mountain lions and bighorns.
Road Notes: Beyond the aggressive topography, all of those switchbacks and one-lane tunnels do present risks for cyclists. Dress brightly and beware blind curves. Plus, there are so many scenic overlooks that it’s hard to get into a rhythm.
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Distance: 68.4 miles
Elevation Gain: 7,329 feet
Starts From: Custer, SD