The Clarks Fork of the Yellowstone is a popular whitewater river run located in the state of Montana. The ideal streamflow range for this river is between 500-2000 cfs, with the best time to experience the river being during the spring and early summer months. The Clarks Fork is rated as a Class IV-V river, making it a challenging run for experienced kayakers and rafters. The segment mileage for this river is approximately 20 miles, starting at the Wyoming/Montana border and ending at the town of Clark.

There are several specific rapids and obstacles to look out for when running the Clarks Fork, including the Devil's Elbow, the Big Timber Rapid, and the Jaws of Death. These rapids are known for their steep drops and powerful currents, making them a thrilling challenge for experienced whitewater enthusiasts.

It is important to note that there are specific regulations in place for the Clarks Fork of the Yellowstone. All boaters are required to obtain a permit from the Forest Service before embarking on the river, and there are restrictions on the number of people allowed in each group. Additionally, all boaters must wear appropriate safety gear, including helmets and life jackets.

Overall, the Clarks Fork of the Yellowstone is a challenging and exhilarating whitewater river run in Montana, with specific regulations in place to ensure both safety and preservation of the natural environment.