Red Rock River

About Red Rock River

The Red Rock River is a remote, approximately 90-mile river in southwestern Montana, flowing from Lillian Lake through the scenic Centennial Valley and ending at Clark Canyon Reservoir. This river offers diverse fly fishing for cutthroat, rainbow, and brown trout, along with mountain whitefish and Arctic grayling. Anglers can find excellent dry fly fishing for cutthroat and grayling in the upper sections, with attractor patterns and standard dry flies like the Adams and Elk Hair Caddis proving effective. Below Lima Reservoir, the fishing shifts to primarily rainbow and some brown trout, with opportunities for larger brown trout in the fall. Key hatches to target include Yellow Sally, Elk Hair Caddis, and Pale Morning Duns, with grasshopper patterns also productive starting in July. While much of the river flows through private land, public access is available at the outlet of Lower Red Rock Lake, below Lima Dam, and on various BLM parcels, with bridge crossings also providing entry points. A 9-foot 5-weight rod is ideal for both dry fly fishing and nymphing on this productive Montana river, though the upper sections are best suited for wading and the lower sections can accommodate some floating with a canoe or inflatable kayak.