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_falls/IDMT094-0670boulder_river_fallspercspfw450hq.jpg)
How the falls moves upstream over time
![How the falls moves upstream over time How the falls moves upstream over time](boulder_river_falls/IDMT094-0671boulder_river_fallspercspfw450hq.jpg)
How the falls moves upstream over time
![Boulder River above the falls Boulder River above the falls](boulder_river_falls/IDMT094-0673boulder_river_fallsspfspfw450hq.jpg)
Boulder River above the falls
![Cascades in Boulder River above the falls Cascades in Boulder River above the falls](boulder_river_falls/IDMT094-0676boulder_river_fallsspfspfw450hq.jpg)
Cascades in Boulder River above the falls
![Cascades in Boulder River above the falls Cascades in Boulder River above the falls](boulder_river_falls/IDMT094-0679boulder_river_fallsspfw450hq.jpg)
Cascades in Boulder River above the falls
![Cascades in Boulder River above the falls Cascades in Boulder River above the falls](boulder_river_falls/IDMT094-0680boulder_river_fallsspfw450hq.jpg)
Cascades in Boulder River above the falls
![Cascades in Boulder River above the falls Cascades in Boulder River above the falls](boulder_river_falls/IDMT094-0682boulder_river_fallsspfw450hq.jpg)
Cascades in Boulder River above the falls
![Cascades in Boulder River above the falls Cascades in Boulder River above the falls](boulder_river_falls/IDMT094-0684boulder_river_fallsspfspfw450hq.jpg)
Cascades in Boulder River above the falls
![Boulder River coming out of tunnel & empty main channel Boulder River coming out of tunnel & empty main channel](boulder_river_falls/IDMT094-0685boulder_river_fallsspfspfw450hq.jpg)
Boulder River coming out of tunnel & empty main channel
![Natural Bridge Falls coming through tunnel at low water Natural Bridge Falls coming through tunnel at low water](boulder_river_falls/IDMT094-0689boulder_river_fallsspfspfw450hq.jpg)
Natural Bridge Falls coming through tunnel at low water
![Boulder River below the falls Boulder River below the falls](boulder_river_falls/IDMT094-0691boulder_river_fallsspfspfw450hq.jpg)
Boulder River below the falls
![Flower at Natural Bridge Falls Flower at Natural Bridge Falls](boulder_river_falls/IDMT094-0666boulder_river_fallscspfw450hq.jpg)
Flower at Natural Bridge Falls
![Flower at Natural Bridge Falls Flower at Natural Bridge Falls](boulder_river_falls/IDMT094-0667boulder_river_fallscspfw450hq.jpg)
Flower at Natural Bridge Falls