Boulder River

The Boulder River originates in the rugged, high elevations of the Beartooth Absaroka Wilderness of the Gallatin National Forest. It free falls down 7,300 vertical feet and runs 60 miles north by northeast through alpine, sub-alpine, mixed coniferous and deciduous forests ,out onto the grasslands, and agricultural ranches before joining the Yellowstone River at Big Timber. The upper main Boulder cuts through a tight glacial valley from its headwaters to the Two-Mile Bridge area. Flowing clear, cold and fast, this 22.5-mile segment combines steep rapids, riffles, long and wide pools, and short stretches of spawning and rearing habitat in a spectacular sub-alpine setting. As the river continues north the next several miles to the Natural Bridge and Falls, it's gradient lessens, resulting in relatively slower moving riffles, runs, and deep pools. Relative is a big word here. The Boulder never seems to run all that slow except when iced up in the middle of winter! Below the Falls, for 4 to 5 miles, the Boulder meanders through agricultural ranchland to its confluence with the East Boulder. This is the area that Rober Redford and the movie crews filmed the movie Horse Whisperer. Its final 28 miles from this point to the mouth are somewhat steeper and readily strewn with boulders and cobbles. It is from shortly below the junction of the East Boulder and Main Boulder at "the Forks" that we often begin our spectacular raft trips. The West Boulder comes in less than a mile downstream from this access point. From here down the river offers anglers an exciting opportunity to wet a fly for the fiesty rainbows and browns ranging from 10-20+ inches living here. You have to be quick, however, as the opportunities are fast and furious. Don't forget to take a break every now and again to look around! It's a ride you won't forget.
Stream Flows
  • Lamar River nr Tower Ranger Station YNP
  • Flow (cfs): 667
    Temperature (°F): 69.08
  • Yellowstone River near Livingston MT
  • Flow (cfs): 4710
    Temperature (°F): 71.06
  • Boulder River at Big Timber MT
  • Flow (cfs): 565
  • Gallatin River near Gallatin Gateway MT
  • Flow (cfs): 752
  • Stillwater River near Absarokee MT
  • Flow (cfs): 1510
    Temperature (°F): 69.08
  • Madison River at Kirby Ranch nr Cameron MT
  • Flow (cfs): 1210
    Temperature (°F): 65.12
  • Madison River bl Ennis Lake nr McAllister MT
  • Flow (cfs): 1490
    Temperature (°F): 76.64
  • Missouri River bl Holter Dam nr Wolf Cr MT
  • Flow (cfs): 3950
    Temperature (°F): 61.7
  • Big Hole River near Melrose MT
  • Flow (cfs): 502
    Temperature (°F): 71.78
  • Beaverhead River at Barretts MT
  • Flow (cfs): 855