The Whitewater River Run is a popular route that runs from the Southern Boundary of the San Gorgonio Wilderness Area to the Northern Boundary of the Whitewater Preserve. This stretch of river is an exciting Class III-IV run that spans approximately 7 miles. The ideal streamflow range for this route is between 500 and 1,000 cubic feet per second (cfs).

The rapids on this section of the river are varied and challenging, featuring large drops, tight turns, and technical maneuvers. Highlights include rapids such as "House Rock," "Staircase," and "The Chute." There are also several significant obstacles to navigate, including boulders, trees, and narrow channels.

In terms of regulations, it is important to note that permits are required for all visitors to the San Gorgonio Wilderness Area, and overnight camping is not allowed in the Whitewater Preserve section of the river. Additionally, all visitors are required to follow Leave No Trace principles and respect the natural environment.

Overall, the Whitewater River Run is a thrilling and challenging route for experienced paddlers. It is essential to check water levels and weather conditions before attempting this run, and to follow all regulations and safety guidelines in order to ensure a safe and enjoyable experience.