On August 6, 1997 I visited Natural Bridge and Falls on the Boulder River.
It was a Montana State Park when I visited it. As of July 2004 it was being transferred to the Forest Service in a land swap.
The "bridge" collapsed in 1988.
The Boulder River, when water flow is low, goes through a tunnel in the rock and then drops over a small falls (which is what it was doing when I visited).
When water flow is high, the river also flows over the top above the tunnel and drops down a 100' falls.
Interesting spot.
How the falls moves upstream over time
How the falls moves upstream over time
Boulder River above the falls
Cascades in Boulder River above the falls
Cascades in Boulder River above the falls
Cascades in Boulder River above the falls
Cascades in Boulder River above the falls
Cascades in Boulder River above the falls
Boulder River coming out of tunnel & empty main channel
Natural Bridge Falls coming through tunnel at low water
Boulder River below the falls
Flower at Natural Bridge Falls
Flower at Natural Bridge Falls