The Gallatin River is a popular destination for whitewater enthusiasts, with the Gallatin Forest Boundary to Blakley Creek segment being a particularly challenging run. The ideal streamflow range for this section is between 1,000 and 3,000 cubic feet per second (cfs), with flows over 3,000 cfs being extremely dangerous. The run is rated as Class III-IV, with several challenging rapids such as House Rock and Mad Mile. The segment covers approximately 8 miles and takes around 2-3 hours to complete.

In addition to the rapids, there are also potential hazards such as strainers and sweepers, which require careful navigation. It is recommended that only experienced whitewater paddlers attempt this run.

Specific regulations for the Gallatin River include a limit on the number of commercial river users, and a requirement for all boaters to wear personal flotation devices (PFDs). The river is also subject to seasonal closures and restrictions to protect fish populations.

Overall, the Gallatin Forest Boundary to Blakley Creek run is a challenging and exciting whitewater experience, but should only be attempted by experienced paddlers with appropriate equipment and caution. Get driving directions.