Tumbling out of the Beartooth Plateau near Nye, Montana, the Stillwater River descends 70 miles of swift boulder gardens and cottonwood flats before joining the Yellowstone at Columbus. Its name is a misnomer—white-water pocket water, not still pools, defines this freestone. Cold, oxygen-rich flows support abundant wild rainbow and brown trout, and a generous public-access corridor makes the river a favorite weekend escape for Billings anglers. From May’s salmonflies to September’s hoppers, the Stillwater delivers classic big-sky dry-fly action with fewer crowds than its famous neighbor downstream.
Anglers divide the river into three zones. **Upper Canyon (Woodbine Campground to Nye)**: steep gradient, big boulders, and pocket-water rainbows—best fished on foot or by raft at moderate flows. **Middle Valley (Nye to Absarokee)**: wider riffle-run sequences and willow islands perfect for drift-boats and summer hopper fishing. **Lower Stillwater (Absarokee to Columbus)**: gentle bends through hay fields; mixed trout and occasional sauger, plus winter tail-out streamer water. Every reach has well-signed fishing access sites (FAS) maintained by FWP.
Wild rainbows dominate (10–17 inches), with browns lurking tight to cut-banks and exceeding 20 inches most autumns. Native Yellowstone cutthroat appear in cooler head-water tribs, while mountain whitefish stack below riffles year-round. The lower river occasionally yields sauger and smallmouth bass drifting up from the Yellowstone. Strict catch-and-release for cutthroat and whitefish safeguards native genetics, while generous limits on browns/rainbows encourage selective harvest in the lower reaches.
Mother’s-Day caddis blanket the Stillwater in late April, igniting the first major surface bite. Early June brings salmonflies and golden stones—big dries tight to boulders move trophy browns. From July through August, hoppers, yellow sallies, and sprinkled PMDs keep trout looking up, while drought-season afternoons push fish into deeper shelves. Fall rainstorms cue blue-winged olive hatches and streamer aggression as browns stage for the spawn. Winter trout drop into tail-outs, sipping midges and nymphs under soft seams.
A 9-foot 6-weight is ideal for tossing size 6–8 salmonfly dries, weighted nymph rigs, and articulated streamers. A 5-weight shines for summer hopper-dropper combos on calmer valley water. Pair 9-ft 3X leaders with big dries; lengthen to 10-12 ft 5X for PMDs and BWOs. Euro-nymphing excels in boulder slots when flows exceed 1,000 cfs. Fall streamer hunters run 6-inch sculpin patterns on sink-tips, swinging through tail-outs at dawn. Always pack throw-bags and helmets when rafting the technical upper gorge.
Woodbine Campground provides trail access to cascades above Nye—deadly with pocket-water dry-droppers. Nye FAS offers a popular put-in for half-day floats to Johnson Bridge. Absarokee Riverside Park grants wading access to meadow bends, while Holmgren Ranch FAS near Columbus is a prime fall streamer launch. Walk-in hunters can follow the West Fork trail (FS 74) for solitude and native cutthroat eager for attractor dries.
High-density FAS sites line Highway 420: Moraine, Cliff Swallow, and Buffalo Jump are favorites for wade anglers. Gravel County Road 419 shadows the river from Absarokee to Columbus, with signage to Holmgren Ranch, Fireman’s Point, and Fisherman’s Point. Flows above 3,500 cfs create Class III wave trains—rafting experience is recommended. USGS gauges at Nye and Absarokee update hourly; target 600–2,000 cfs for optimal fishing and safer wading.
Flies: salmonfly and golden-stone dries (#6-10), rubber-leg stone nymphs (#4-8), PMD sparkle duns (#16), hopper patterns in tan/peach (#8-10), olive or black sculpin streamers (#4), and tungsten pheasant-tails (#14-18). Gear: 6-wt rod with floating and intermediate sink-tip lines, polarized glasses, breathable waders, and studded boots for slick granite slabs. In midsummer bring lightweight wet-wading shoes. A throw-rope, PFD, and helmet are mandatory for anyone floating white-water sections.
Irrigation withdrawals, whirling disease, and bank erosion threaten trout habitat. **Stillwater Valley Watershed Council** coordinates riparian fencing and bank-stabilization with local ranchers. **Montana Trout Unlimited** funds side-channel reconnections and temperature monitoring stations. Anglers can help by practicing clean-drain-dry protocols to fight aquatic invasives, packing out trash, and supporting voluntary drought angling closures (hoot-owl) when water exceeds 73 °F.
Snow-melt peaks in late May and can push flows above 5,000 cfs—too dangerous for wading. Always scout rapids like Beartooth Drop and Woodbine Chutes before committing a raft. Afternoon storms roll off the Beartooths with lightning and golf-ball hail; carry a weather radio and seek high-ground exits. Grizzly sightings are rare but increasing—pack bear spray when fishing head-water tribs. Winter shelf-ice collapses without warning; wear studs and avoid under-cut banks.
**Stillwater Anglers** (Columbus) posts daily flow updates, rents rafts, and stocks custom salmonfly dries. **East Rosebud Fly & Tackle** (Billings) carries extensive Stillwater patterns, Euro-nymph gear, and offers shuttle coordination. **Big Sky Fly Shop** in Livingston provides regional hatch intel and multi-day guide packages that pair the Stillwater with the Yellowstone. All three shops welcome beginners and sell Montana licenses on site.
The **Stillwater Valley Watershed Council** hosts river clean-ups and native-planting days each spring. **Montana Trout Unlimited** coordinates whirling-disease monitoring and youth education on the Stillwater and Yellowstone basins. **Clark Fork Coalition** supplies scientific data on sediment transport that inform local restoration projects. Donating to or volunteering with these nonprofits keeps the river cold, clean, and connected for future anglers.
The Stillwater River is in FWP’s Central & Eastern District (Region 5). From Woodbine Campground downstream to the Yellowstone confluence, the combined trout limit is five daily and ten in possession, no more than one over 18 inches. Catch-and-release is mandatory for cutthroat trout statewide. Hooks must be single-point when using live bait; however, most anglers fish artificial flies or lures only. A valid Montana fishing license is required for everyone 12 and older. Always review the annual regulation booklet for seasonal closures, hoot-owl restrictions, and emergency fire-related access bans before fishing.