The Whitewater River run begins at the headwaters in the Mystic Lake Basin on the north side of Mount Rainier and runs to the northern boundary of Mount Rainier National Park in Washington state. This run is ideal for experienced kayakers and rafters, with a recommended streamflow range of 500-3000 cfs. The class rating for this run is class III-IV, with some difficult class V rapids in certain sections. The segment mileage for this run is approximately 14 miles.

There are several notable rapids and obstacles on this run, including the Entrance Exam, Chaos, and the Narrows. These rapids require expert navigation skills and are not recommended for novice paddlers. It is also important to note that Mount Rainier National Park has specific regulations for the Whitewater River run, including a limit on the number of permits issued per day and a requirement for all paddlers to have appropriate safety equipment.

Sources:

- American Whitewater: https://www.americanwhitewater.org/content/River/detail/id/1693/
- Mount Rainier National Park: https://www.nps.gov/mora/planyourvisit/upload/Whitewater-River-Permit-Application.pdf