Tunnel Rock is a chalky white rock formation in the canyon of the Niobrara River, between Sparks and Norden in Keya Paha County. The river and weather have worn an opening through the rock, which gives it its name. It can be seen from the county road between Sparks and Norden, and river outfitters point it out on float trips down this stretch of the Niobrara National Scenic River.
Tunnel Rock has drawn visitors for more than a century. A 1912 photograph is captioned "Tunnel Rock, Keya Paha County, Neb." In the 1930s, Nebraska filmmaker George Wentz filmed it for his travel films of the state. His title card calls it "a chalk rock formation in Niobrara Canyon," and the footage shows five people standing on top and two in the opening. The film is in the History Nebraska collection.
The Niobrara canyon in this area is cut through layers of soft sandstone and siltstone laid down millions of years ago, the same layers that form the river's bluffs and waterfalls.
Visiting: The land along the river here is mostly private. Please view Tunnel Rock from the road or from the river, and do not climb it or cross private land without the owner's permission.