Spearfish Canyon: Four Hundred Million Years in Nineteen Miles

Spearfish Creek carved this canyon. That sentence sounds simple, and over the span of a human life it is. Over more than three hundred million years, it is one of the stranger geological achievements on the continent.

The limestone walls rising above the road on United States Highway Fourteen A were laid down when the Black Hills region was submerged beneath a warm, shallow tropical sea during the Mississippian Period, roughly three hundred forty million years ago. Coral reefs formed on the floor of that sea. The reefs died and compressed into limestone. The region then rose, tilted, eroded. The creek found the soft limestone and began cutting. It is still cutting.

The canyon runs roughly nineteen miles between Spearfish, at the northern end, and Cheyenne Crossing, at the southern junction with United States Highway Sixteen. The walls in places rise over one thousand feet above the road. Spearfish Creek, a cold-water stream fed by springs and snowmelt from the high hills above, runs alongside the road for the entire length and supports a trout fishery that fly fishermen drive hours to reach.

Bridal Veil Falls drops off the canyon wall near the southern end, a thread of water three hundred twenty feet tall in wet seasons. The waterfall is visible from the road.

Two scenes in the film 'Dances with Wolves,' released in nineteen ninety, were shot in this canyon, using the limestone walls as a stand-in for the Plains landscape the production needed.

The canyon has been carrying water for more than three hundred million years. It has been carrying tourists for about one hundred thirty.