Big Sky South (snowmo)
Big Sky South (snowmo) Trail is a 39.3 miles snow trail in Custer Gallatin National Forest, Montana. The Forest Service rates it trail class 3, developed. It is open to snowmobile, snowshoeing and cross-country skiing.
Trail conditions, closures and hazards are not tracked here. The Custer Gallatin National Forest official page carries current alerts and closure orders.
Map
One end Other endLine simplified to about 100 metres. Basemap from the USGS National Map.
| One end | 44.7661, -111.1130 · Directions ↗ |
| Other end | 45.0703, -111.1972 · Directions ↗ |
The ends are the two ends of the longest connected chain of segments. The record does not say which is the usual start. The trail is recorded as 5 segments.
The trail
| Length | 39.3 miles |
| Trail class | 3, developed |
| Type | snow trail |
| Surface | native material |
| Typical grade | 12-20 percent |
| Typical tread width | 18-24 inches |
| Motor vehicles | Open to at least one motorized use |
| Accessibility | Not evaluated |
| Trail numbers | 914 |
| Forest | Custer Gallatin National Forest (unit 0111) |
| States | Montana |
| Detail published | management level, with uses |
Values are the set across all segments. Class 1 is minimally developed and class 5 is fully developed. Grade and width are the forest's typical values, not measured extremes.
Weather by month
Allowed uses
| Snowmobile | Allowed year-round |
| Snowshoeing | Allowed year-round |
| Cross-country skiing | Allowed year-round |
A use is listed when the Forest Service records it as managed, accepted or discouraged on any segment. Discouraged still means legal. Uses marked restricted are left out. Where the forest publishes a Motor Vehicle Use Map, that map governs motorized use.
Trailheads
The Forest Service recreation layer records no trailhead within a third of a mile of this trail's line. Many trails start from a road pullout or another trail with no trailhead record. The forest's recreation pages list the trailheads it does publish.
Camping nearby
Campsite Atlas cards carry site counts and booking links from Recreation.gov. Forest Service cards come from the recreation layer and link the agency page.
Fire nearby
- PrescribedLonesome Wood Rx Unit 31B
16 mi from the trail midpoint
Distance is to the reported incident point, not the fire edge. Closure orders are on the forest's official page.
Explore
Reference
Questions people ask
How long is the Big Sky South (snowmo) Trail?
39.3 miles, the sum of the 5 segments the Forest Service records under this name in Custer Gallatin National Forest.
Source: Forest Service trail layer
What is allowed on the Big Sky South (snowmo) Trail?
snowmobile, snowshoeing and cross-country skiing. The trail is open to at least one motorized use.
Source: Forest Service trail layer
Where does the Big Sky South (snowmo) Trail start?
The line begins at 44.7661, -111.1130 and ends at 45.0703, -111.1972. No Forest Service trailhead is recorded within a third of a mile of it. The record does not say which end is the usual start.
Source: Forest Service trail layer
Is the Big Sky South (snowmo) Trail in a wilderness area?
No. The trail line does not cross any polygon in the National Wilderness Preservation System layer.
Source: Wilderness Connect
Where can I camp near the Big Sky South (snowmo) Trail?
Cabin Creek Cabin (0.1 mi), Wapiti Cabin (2.1 mi) and Beaver Creek Cabin (3.1 mi) are within five miles of the trail. Site counts and booking links are on Campsite Atlas.
Source: Campsite Atlas
How developed is the Big Sky South (snowmo) Trail?
Trail class 3, which the Forest Service describes as developed. Class 1 is a minimal, unimproved route and class 5 is fully developed, often paved.
Source: Forest Service trail layer
How steep and how wide is the Big Sky South (snowmo) Trail?
The typical grade is 12-20 percent. The typical tread is 18-24 inches wide.
Source: Forest Service trail layer
Who manages the Big Sky South (snowmo) Trail?
Custer Gallatin National Forest, Forest Service unit 0111. The trail is in Montana.
Is there a fire near the Big Sky South (snowmo) Trail?
1 active incident within 50 miles of the trail midpoint as of 2026-09-18, the nearest Lonesome Wood Rx Unit 31B at 16 miles. Check the forest's closure orders before you go.
Source: Fire nearby
Source
This page is built from 5 segments named BIG SKY SOUTH (SNOWMO) in the Forest Service TrailNFS_Publish layer, administrative unit 0111. Wilderness overlap is tested against the National Wilderness Preservation System layer from Wilderness Connect. Trailheads and Forest Service campgrounds come from the Forest Service Recreation Opportunities layer. Data refreshed September 18, 2026. The methodology page explains how segments become trails.