The Henry's Fork Snake River, a major tributary of the Snake River, originates at Big Springs in eastern Idaho and flows south for approximately 127 miles before joining the Snake River. This pristine waterway drains the eastern slopes of the Yellowstone Plateau and western slopes of the Teton Range, carving through volcanic canyons and lush forests.

Paddlers can experience a range of conditions on the Henrys Fork, from placid flatwater to challenging whitewater. The Big Springs Water Trail offers a gentle 4.5-mile float suitable for beginners and families, winding through scenic meadows from Big Springs Campground to Mack's Inn. More advanced paddlers can tackle the exhilarating Box Canyon to Last Chance section, a 5.5-mile Class II run featuring deep pools and swift currents through a dramatic black lava gorge.

For those seeking serious whitewater, the Sheep Falls Run delivers with three Class V rapids - Sheep Falls, Son of Sheep, and Gun Sight - interspersed with Class III-IV rapids over its approximate 5-8 mile length. Scouting is essential on this expert-level stretch. The Coffee Pot Rapids section provides a thrilling Class III-IV experience through rocky canyons with views of the Centennial Mountains.

Spring runoff typically peaks in May and June, with stable summer flows ideal for fishing and paddling. The river corridor hosts diverse wildlife, including moose, osprey, and native Yellowstone cutthroat trout. Towering Mesa Falls, accessible via boardwalks, offers a spectacular riverside attraction.

Key access points include Island Park, Ashton, and St. Anthony. Paddlers should be aware of irrigation diversions, especially below Ashton. The Henrys Fork's pristine waters and world-class fly fishing have made it an iconic western river. With proper precautions, multi-day trips are possible on some sections, allowing paddlers to fully immerse themselves in this remarkable Idaho waterway.