Smith Falls State Park in Keya Paha County protects a remarkable 63-foot waterfall where a spring-fed creek drops over a sandstone ledge into the Niobrara River — the tallest waterfall in Nebraska, and a startling sight in a state most people associate with flat grassland. The 3-mile round trip to the falls crosses a suspension bridge over the Niobrara, follows the canyon rim through a boreal forest of spruce and birch that seems out of place at this latitude, and arrives at a misting curtain of water framed by ferns and wildflowers.

The Niobrara National Scenic River corridor here is one of the biological crossroads of North America, where six distinct ecosystems overlap: ponderosa pine forest from the west, eastern deciduous forest, Rocky Mountain flora, boreal species, tallgrass prairie, and mixed-grass prairie. This unusual convergence means the trail passes through a different plant community every quarter mile. The river itself is legendary for float trips by canoe and kayak, and many visitors pair a hike with a half-day paddle through the canyon.

Smith Falls State Park charges $8/vehicle for non-Nebraska vehicles. Dogs are allowed on leash. The park is open April through October; the road can be rough. No permit required. The nearest services are in Valentine, about 18 miles east on US-20.