Overview
The Stillwater River has a reputation among Montana fly fishers that extends well beyond state lines. Its name is something of a misnomer the Stillwater runs fast and clear over cobbled riffles, holding substantial populations of brown and rainbow trout. The trail that follows it offers one of the most pleasant low-elevation hikes in the Custer Gallatin National Forest, and it is genuinely accessible without the altitude demands that govern most of the forest's trail network.
At just 400 feet of gain over six miles, this is an easy walk rather than a challenging hike. The path stays close to the river through most of its length, alternating between riparian corridors of cottonwood and willow and open pine forest on the lower slopes above the river. Late May and June bring exceptional wildflower displays in the meadow sections. The combination of easy terrain, early-season access, and a beautiful river makes this trail an underused gem in a forest better known for its high-altitude routes.
The Stillwater drainage also serves as a different kind of gateway to the Beartooth country. Parties planning multi-day backpacking trips on the plateau sometimes stage from the Stillwater and gain elevation via longer approaches that avoid the highway corridor. But for a straightforward day out, you do not need any such ambitions. Three miles along the river and back is a full and satisfying day.
The Route
Miles 0 to 2: Trailhead to River Bend
From the parking area, the trail descends briefly to the river level and then follows the Stillwater upstream through a dense riparian zone. Cottonwood trees dominate the first mile, providing shade that is welcome in the summer heat. The path is wide and well-worn, with minimal obstacles. At about mile 1.5, the river makes a pronounced bend around a gravel bar that is a popular lunch spot and wading area when water levels allow.
Miles 2 to 3: Upper Riparian Corridor
The second half of the outbound walk transitions from cottonwood to pine and Douglas fir as the trail rises slightly above the river. Views open up in both directions downstream toward the plains and upstream toward the Beartooth foothills. The river is audible throughout this section and visible in most places, with multiple side paths leading down to the bank. The turnaround point at mile 3 is not marked; simply choose a spot with a good view or a flat rock by the water and call it your destination before retracing the route.
When to Visit
This is one of the earliest-opening trails in the southern Custer Gallatin area, typically accessible by late April or May. The river runs highest during spring snowmelt in May and June a good time for wildflowers and bird watching along the corridor. Summer through early fall brings more stable river levels and warmer temperatures. September and early October offer fall foliage in the cottonwood groves.
Before visiting, check current conditions using the resources in our conditions-checking guide.
What to Bring
Many hikers carry the following for the Stillwater River Trail:
- 1-2 liters of water (filter available from the river if needed)
- Sunscreen; sections of the trail are exposed
- Insect repellent in late spring and early summer
- Bear spray (standard precaution in this drainage)
- Fishing gear if holding a valid Montana license
Individual needs vary. The easy terrain means physical demands are low, but river access means some hikers prefer waterproof footwear.
Practical Details
No permit is required for day hiking as of 2026. The trailhead has no formal fee station. Dispersed camping is permitted along the river corridor in areas not designated otherwise; follow Leave No Trace principles near water sources and keep camp at least 200 feet from the riverbank where terrain allows.
The America the Beautiful pass is not required for this trailhead as it does not charge a day-use fee. Veterans can review pass benefits and fee waiver programs in our veteran benefits guide.
Getting There
From Columbus, Montana (on I-90, approximately 50 miles east of Billings), drive west on US-78 toward Absarokee, then turn west on the road to Fishtail and the Stillwater River drainage. The trailhead is accessed via county and forest roads; a current Custer Gallatin motor vehicle use map from the Beartooth Ranger District in Red Lodge will have the precise road numbers. The lower portion of the route is accessible by most vehicles; high-clearance is helpful beyond the pavement.