The Spring Gulch Headwaters to Mainstem segment of the Whitewater River Run in Montana is a popular destination for whitewater enthusiasts. The ideal streamflow range for this run is between 500 and 2,500 cubic feet per second (cfs), with higher flows creating more challenging rapids. The segment covers a distance of approximately 10 miles and is rated as Class III-IV, with several difficult rapids and obstacles including "Pinball," "The S-Turn," and "The Ledge."

Specific regulations to the area include permits, which are required for commercial outfitters and guides. Private boaters are also required to have a permit, which can be obtained through a lottery system. Additionally, there are restrictions on camping, fires, and human waste disposal within 200 feet of the river.

According to the Montana Whitewater website, this segment of the Whitewater River Run "offers a great combination of scenery, whitewater, and wilderness adventure." However, it is important for paddlers to have experience with Class III-IV rapids and to take proper safety precautions, including wearing appropriate gear and running the rapids with a partner.

Overall, the Spring Gulch Headwaters to Mainstem segment of the Whitewater River Run is a challenging and scenic destination for experienced whitewater enthusiasts, with specific regulations in place to protect the area and ensure visitor safety.