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Historic place

Iron Mountain Road

US Highway 16A (Iron Mountain Road), Keystone, SD

Senator Peter Norbeck built three wooden "pigtail" bridges that spiral drivers back over their own road, and aimed each of the highway's rock tunnels so precisely that Mount Rushmore appears framed dead-center through the opening.

📅 1933–present🏛️ Scenic RoadStill hereBuilt 1933
Open on the mapSlide back to 1933

The story

Iron Mountain Road (US-16A between Keystone and Custer State Park) was completed in 1933 under Senator Peter Norbeck, who chose its winding layout and pushed the project through even after engineers said it couldn't be built. Rather than a straight, efficient route, Norbeck wanted the landscape revealed gradually. Its signature features are three spiraling wooden "pigtail bridges" (designed 1932 by Cecil Clyde Gideon) that loop the road over itself on steep grades, and tunnels blasted so their openings frame Mount Rushmore's faces as you approach from the south.

Everything that was here

Did you know?

Norbeck reportedly said he wasn't building the road to save ten minutes, but to reveal as much scenery as possible.
The three wooden pigtail bridges spiral the road back over itself to manage the steep grade.
Several tunnels were deliberately aligned so Mount Rushmore appears framed in the opening.

Connected places

Dinosaur Park

Rapid City, SD
Mount Rushmore

Paul Bunyan and Babe the Blue Ox

Bemidji, MN
Mount Rushmore

Explore the full web of connections on the map.

Nearby history

Mount Rushmore National Memorial

13000 SD Highway 244 · 2.3 km away
Sculptor Gutzon Borglum blasted 450,000 tons of granite off a Black Hills peak to carve four 60-foot faces — and died in

Holy Terror Mine

Base of Mount Aetna (Keystone) · 4.3 km away
Legend says a Black Hills prospector named his richest strike after his own wife — not as a tribute, but as a joke about

Spokane (ghost town)

Spokane townsite (~16mi NE of Custer) · 5.4 km away
Deep in Black Hills National Forest sits one of South Dakota's best-preserved ghost towns — a mining camp that didn't hi

Needles Highway

SD Highway 87 (Needles Highway) · 8.6 km away
Governor Peter Norbeck personally walked and rode horseback over every foot of the route before a single machine touched

Sylvan Lake

Sylvan Lake, Custer State Park · 10.0 km away
This granite-ringed "jewel of the Black Hills" predates Custer State Park by three decades — and in 2007 it stood in for

Custer State Park & State Game Lodge

US Highway 16A (State Game Lodge) · 11.9 km away
President Calvin Coolidge ran the country from a rustic Black Hills lodge for three months in 1927, sleeping a stone's t

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Sourceshttps://www.custerresorts.com/activities/scenic-drives/iron-mountain-road