Difficulty III-V
Length 4 Miles
Gauge Boulder River at Big Timber MT
Flow Range 1000 - 5000 CFS
Flow Rate as of: 1 hour ago 196 [CFS] ℹ️
Reach Info Last Updated 11/12/2019 7:07 pm

River Description

Hells Canyon of the Boulder is a high quality whitewater run set in a spectacular valley.  A bit of flat water leads to a massive rapid that is a portage for most or all paddlers.  A bit more chill water leads to the class IV/IV+ canyon section.  The rapids are often pretty long and continuous, and several have distinct moves to be made to boof or avoid big holes.  We paddled it at 1600 and the rapids were plenty juicy and distinct.  Flows in the 3500 range are rumored to yeild Class V big water rapids that are long, continuous, and connected.  After 5-10 good rapids the whitewater eases off but remains fun to the takeout. . 

Rapid Descriptions


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Paul Heffernan
3 years ago

There are 3-4 new logs across the river in this section. I paddled it at 1400cfs. All wood in this section was new (looked as though the storm the day before was the culprit). Not sure if high water typically clears this section or if logs might remain for a while.

Gage Descriptions

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Directions Description

We have no additional detail on this route. Use the map below to calculate how to arrive to the main town from your zipcode.

No Accident Reports



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Appeal Challenging Montana Navigability Is Denied

Jason Robertson

On May 28 the U.S. Supreme Court denied an appeal by Mountain States Legal Foundation who filed a lawsuit in June 2001 alleging the 1985 Montana Stream Access Law violated their rights under the U.S. Constitution to regulate who floated over their land.

The decision thereby protects Montana's Stream access law and public rights of navigation throughout the State.

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River Recreationists Win Big in Montana!

Jason Robertson

The Missoulian newspaper reported on January 5th, 2001 that U.S. District Judge Charles C. Lovell dismissed a case brought by the Mountain States Legal Foundation challenging public recreational rights on Montana’s rivers and streams. This is a huge win for boaters and fishermen!

Kevin Colburn


David Schroeder


Revision #Revision DateAuthorComment
1213883 11/12/19 Kevin Colburn updated image position
1212205 05/08/19 Kevin Colburn updated image position
1190781 01/18/02 David Schroeder n/a
1197976 07/24/10 Kevin Colburn Added river reach description
1212189 05/08/19 Kevin Colburn updated image position
1212190 05/08/19 Kevin Colburn updated image position