The Whitewater River run in Montana, from Absaroka-Beartooth Wilderness Boundary to Headwaters, Sec. 20, T9S, R17E, is a challenging class III-IV whitewater experience. The ideal streamflow range for this run is between 500-1000 cfs, which is typically in late spring to early summer. This segment covers 10.8 miles and is known for its steep gradient and continuous rapids, making it a popular destination for intermediate to advanced paddlers.

The river features several noteworthy rapids, including Pinball, Ledge Drop, and The Squeeze. Pinball is a series of boulder-choked drops that require precise maneuvering. Ledge Drop is a steep and technical rapid that requires careful scouting. The Squeeze is a narrow channel with a sharp turn that requires quick reflexes and precise navigation.

There are specific regulations to the area that paddlers should be aware of. The Beartooth Ranger District requires all boats to be registered and have a permit, which can be obtained at the district office. Additionally, there are strict guidelines for camping and fires, as well as regulations for the use of motorized watercraft.

Overall, the Whitewater River run is a thrilling and challenging whitewater experience for experienced paddlers. It is essential to check the streamflow levels and be aware of the specific regulations in the area before embarking on this adventure.