The Whitewater River Run on the Fisher River in Montana is a popular destination for whitewater enthusiasts. The ideal streamflow range for this run is between 800 and 1500 cubic feet per second (cfs), which typically occurs during spring runoff. The class rating for this run is Class III to IV, with approximately 13 miles of rapids and obstacles.

The segment mileage for this run is approximately 10 miles, starting at the junction of the Fisher River, three miles downstream of Libby Dam, and ending at Tub Gulch, four miles upstream from the town of Libby. Specific river rapids and obstacles include Hell's Half Mile, a Class IV rapid, as well as several Class III rapids such as Jaws and The Narrows.

There are specific regulations to the area, such as a permit requirement for commercial outfitters and a requirement for personal flotation devices (PFDs) for all participants. Additionally, there are restrictions on the use of motorized watercraft on the Fisher River.

Overall, the Whitewater River Run on the Fisher River offers a thrilling adventure for experienced whitewater enthusiasts. While the rapids and obstacles can be challenging, the ideal streamflow range and Class III to IV rating make for an exhilarating ride.