About
Clarks Fork of the Yellowstone, Wyoming — Sunlight Basin. William Clark's name found its way onto this river through the 1804–1806 Lewis and Clark Expedition, the journey that produced the first American survey of the region. That historical lineage still shapes how the river is regarded today. The Clarks Fork descends from the 13,200-foot Beartooth Plateau and the eastern slope of the Absaroka Range, threading through Park County before entering Montana. The descent compresses a great deal of geology and elevation into a comparatively short river — the Wyoming reach runs 26 miles, carrying an average flow of 1,685 cubic feet per second.
Long before the surveyors and the timber crews, the valley belonged to the region's Indigenous nations. The Clarks Fork flowed through their ancestral territory and served as a primary travel corridor, a hunting ground, and a gathering place. That history is woven through the river's later chapters — the treaties of the 1800s, the cession framework of the allotment era — but the river itself predates all of it, a fixed line of moving water through country that has changed hands many times.
The forest through which the Clarks Fork flows holds its own foundational place in American conservation. Shoshone National Forest, established in 1891, was the first national forest in the United States, and the Clarks Fork has run through that protected ground ever since. The watershed carried a working past as well: from the 1830s into the 1920s, local sawmills, logging drives, and downstream lumber operations worked the timber to feed regional industry and railroad expansion. The exhaustion of the old-growth stands and the rise of state forestry conservation in the early twentieth century brought that large-scale logging to an end.
On November 28, 1990, Congress added the upper 6.7 miles of the Clarks Fork within Wyoming to the National Wild and Scenic Rivers System, safeguarding the corridor's free-flowing character. The managing agency is the Bureau of Land Management. The protected reach drains the Sunlight Basin and the Crandall Creek area — terrain counted among the most pristine in the Greater Yellowstone Ecosystem, supporting native Yellowstone cutthroat trout, mountain goat, bighorn sheep, and grizzly bear. The river was already inside the Shoshone National Forest; the 1990 designation added a second layer of federal oversight aimed specifically at the hydrology and riparian corridor.
The scale of that hydrology becomes clear in the record. The 1997 flood on the Clarks Fork reached 33,000 cubic feet per second at the Wyoming gauge — the largest recorded flow of the twentieth century on this river, and close to twenty times the average discharge of 1,685 cubic feet per second measured at USGS station 06274300. The optimal flow window runs between 850 and 2,550 cubic feet per second, a range that reflects the river's transition from low, rock-strewn conditions to moving water with real consequence. For backcountry anglers, the native Yellowstone cutthroat remains the consistent draw — fish in a watershed that Congress deliberately chose to keep wild.
River conditions are community-verified. CFS ranges, difficulty ratings, and access points may not reflect every flow level or seasonal change. Always check current conditions, scout unfamiliar rapids, and paddle within your skill level.