Big Flat Creek is a popular whitewater river run located in northern California. The ideal streamflow range for the creek is between 400-800 cfs, with the best times to run the creek being in the spring and early summer months. The creek is rated as a Class III-IV river, with several challenging rapids and obstacles along the way.

The segment mileage of the Big Flat Creek is approximately 10 miles, with the river starting at the Big Flat Campground and ending at the junction with the Trinity River. Some of the notable rapids and obstacles on the creek include Drop and Suck, Leap of Faith, and Last Chance.

There are specific regulations in place for those who wish to run the Big Flat Creek. A permit is required to access the creek, and only non-motorized watercraft are allowed on the river. Additionally, visitors are required to pack out all trash and follow Leave No Trace principles.

Overall, Big Flat Creek offers a thrilling whitewater experience for experienced paddlers. It is important for visitors to follow regulations and practice safety while on the river.