The Whitewater River Run from Confluence with Chinook Creek to Southern Boundary of Mount Rainier National Park in the state of Washington is a popular destination for whitewater enthusiasts. The ideal streamflow range for this run is between 800 and 1500 cubic feet per second (cfs). The class rating for this run is between III and IV, making it a moderately challenging run for experienced paddlers. The total segment mileage for this run is approximately 6.5 miles.

There are several notable rapids and obstacles on this run, including the Entrance Rapid, the S-Turn, the Pinball, the Slot, and the S-Turn Slide. Each of these rapids presents its own unique challenge to paddlers, and extra caution should be taken when navigating them.

In addition, there are specific regulations in place for this area. Paddlers are required to obtain a permit from Mount Rainier National Park before embarking on this run. Additionally, all paddlers must wear personal flotation devices (PFDs) at all times while on the river.

Overall, the Whitewater River Run from Confluence with Chinook Creek to Southern Boundary of Mount Rainier National Park provides a thrilling whitewater experience for paddlers with the necessary skills and experience. However, it is important to always prioritize safety and follow all regulations and guidelines to ensure a safe and enjoyable experience.