The Whitewater River run located in Montana is a popular destination for thrill-seeking kayakers and rafters. The segment of the river that runs from Mainstem Headwaters, Sec. 4, T15N, R18W to Boundary, Sec. 2, T13N, R18W is approximately 36 miles long and has a class rating of III-IV. The ideal streamflow range for this section of the river is between 500-2000 cfs.

The river rapids and obstacles that one can expect to encounter on this run include several class III rapids such as Jaws, Split Rock, and Deadman's Drop. There are also a couple of class IV rapids, including Devil's Elbow and Fang.

It is important to note that this section of the river is located on private property, so visitors must obtain permission from the landowner before accessing the river. Additionally, there are no regulations specific to this area, but all Montana state boating laws apply.

Overall, the Whitewater River run offers a thrilling experience for experienced kayakers and rafters, but caution should be exercised due to the powerful rapids and potential hazards. It is recommended to check local weather and water conditions before embarking on this run.