The North Fork of the South Platte River, also known as the Whitewater River Run, starts at the small community of Insmont and flows for approximately 16 miles to the take-out point at the Estabrook picnic area. This stretch of river is rated as a Class III-IV and is best navigated at a flow range of 250-800 cubic feet per second (cfs).

This section of river offers an exciting and challenging run for experienced kayakers and rafters. The rapids on this stretch include Zig Zag, Devil's Slide, Hole in the Wall, and Staircase. These rapids can be technical and require good boat control and the ability to make precise moves.

The North Fork of the South Platte River is regulated by the Colorado Parks and Wildlife. Rafters and kayakers are required to wear personal flotation devices and follow all safety guidelines outlined by the agency. Additionally, this section of river is closed to boating from November 1st through May 31st to protect wintering wildlife.

In summary, the North Fork of the South Platte River offers a challenging and exciting run for experienced boaters with a range of Class III-IV rapids. The ideal streamflow range is between 250-800 cfs and boaters must follow all Colorado Parks and Wildlife regulations for safety and conservation purposes.