The Bill Williams River is a popular whitewater river run located in the state of Arizona. The ideal streamflow range for this river run is typically between 1,500 and 4,500 cubic feet per second (cfs), with the best flows occurring in the spring and early summer months. The class rating for this river run ranges from Class II to Class III, making it suitable for intermediate-level kayakers and rafters.

The segment mileage for the Bill Williams River run is approximately 40 miles, with the most popular section being the 20-mile stretch between Alamo Lake and Lake Havasu. This section features a number of challenging rapids and obstacles, including the “Toilet Bowl” rapid, which is known for its swirling eddies and challenging hydraulics.

In addition to its challenging rapids, the Bill Williams River is also subject to a number of specific regulations that are designed to protect the area's fragile ecosystem. These regulations include restrictions on camping and fires, as well as limits on the number of visitors allowed in the area at any given time. Visitors are also required to obtain a permit before entering the area, and are expected to follow all posted signs and regulations to help protect the natural environment.

Overall, the Bill Williams River is a challenging and exciting whitewater river run that offers a unique and rewarding experience for intermediate-level kayakers and rafters. However, visitors should be aware of the specific regulations and guidelines that apply to the area, and should take care to follow these rules in order to help protect the natural environment for future generations.