When anglers speak of the Bighorn River, they almost invariably mean the famed Fort Smith tailwater in Montana — the blue-ribbon stretch below Yellowtail Dam that has produced world-class brown and rainbow trout for decades. But the Bighorn actually begins its life 100 miles upstream in Wyoming, emerging from the Wind River Canyon near Thermopolis in what is arguably the most dramatic trout river canyon in the Rocky Mountain West. The Wyoming Bighorn is a different fishery — wilder, more variable, and less known — but for the explorer-angler, it holds a special appeal that the crowded Fort Smith reach simply cannot match.
The Wyoming Bighorn originates at the famous Wedding of the Waters, the remarkable geographic curiosity where the Wind River officially becomes the Bighorn River. This transition happens not at a confluence but simply because the river crosses from the Wind River Indian Reservation into Fremont County — the same water, continuous, is renamed. From here, the Bighorn cuts northward through the spectacular Wind River Canyon, a deep sandstone gorge where the river drops through Class II-III rapids between long pools holding good populations of brown trout and rainbow trout.
The canyon section is primarily a float fishery — the walls are sheer in many places, making wade access limited to specific boat ramps and pullouts. Experienced oarsmen running drift boats or rafts can access the finest stretches of canyon water, though the rapids require competent river craft skills. Below the canyon near Thermopolis, the river broadens and slows into classic tailwater-style water that can be waded effectively in normal flows.
Brown trout dominate the Wyoming Bighorn, averaging 12 to 16 inches with fish pushing 20 inches common for those who know the productive pools and overhanging banks. The morning caddis hatch from May through September is reliable and can be exceptional on warm evenings. Salmonfly and golden stone hatches in late June draw the largest fish to the surface.
The stretch near Thermopolis benefits from thermal spring water inputs, which moderate winter temperatures and keep fish active year-round. Hot Springs State Park provides free public access to the river through the park, and the bison herd roaming the park adds an authentic Wyoming backdrop to your fishing day. Fall is a sleeper season on the Wyoming Bighorn — dropping hopper and caddis patterns in September and October produces surprising numbers of fish as browns begin their pre-spawn staging behavior.
