The Selway-Bitterroot Wilderness Boundary to Headwaters section of the Whitewater River Run is a breathtaking 47-mile stretch in north-central Idaho. This section of the river is rated Class III-IV, and the ideal streamflow range for this section ranges from 1,500 to 5,000 cfs. This section of the river features thrilling rapids such as Ladle, Horseshoe, and Sudden Death, and also offers abundant opportunities for trout fishing.

The segment mileage for this section of the river is 47 miles, and it takes roughly 4-5 days to complete the journey. However, it's important to keep in mind that this section of the river is only accessible by permit, and there are specific regulations that must be followed in order to preserve the wilderness environment.

Some of the regulations for the Selway-Bitterroot Wilderness Boundary to Headwaters section of the Whitewater River Run include packing out all waste and garbage, camping in designated areas, and adhering to strict fire regulations. In addition, all boaters must obtain a permit in advance from the U.S. Forest Service, and there is a strict limit on the number of permits issued each year.

Overall, the Selway-Bitterroot Wilderness Boundary to Headwaters section of the Whitewater River Run is a thrilling and challenging adventure that offers stunning wilderness views and exciting rapids. However, it's important to plan carefully and follow all regulations in order to preserve the natural environment and ensure a safe and enjoyable trip.