The Wilderness Boundary to Headwaters section of the Whitewater River in Idaho is a popular destination for advanced paddlers looking for a challenging run. The ideal streamflow range for this section is between 500 and 1,000 cubic feet per second (cfs), with higher flows making the rapids more intense. The class rating for this section ranges from class III+ to IV+ depending on the flow.

The segment mileage for this section is 20.2 miles, with several notable rapids and obstacles along the way. One of the most challenging rapids is called "Punch Bowl," which is a steep drop that requires precise navigation. Another significant obstacle is "Hell Hole," a large boulder that creates a powerful hydraulic that can trap paddlers.

There are specific regulations in place for the Whitewater River run, including a permit system and restrictions on group size. Paddlers must obtain a permit from the Forest Service before entering the wilderness area, and groups are limited to no more than 12 people. Additionally, all paddlers must carry a "leave no trace" ethic and pack out all trash.

Overall, the Wilderness Boundary to Headwaters section of the Whitewater River is a challenging and exciting run for experienced paddlers. It is important to follow all regulations and safety guidelines when paddling this section to ensure a safe and enjoyable trip.