Custer Gallatin National Forest · Montana · Trail 900

Big Sky North (snowmo)

Big Sky North (snowmo) Trail is a 65.5 miles snow trail in Custer Gallatin National Forest, Montana. The Forest Service rates it trail class 2 to 4, moderately developed to highly 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 end45.5309, -111.1354 · Directions ↗
Other end45.1015, -111.2190 · 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 6 segments.

The trail

Length65.5 miles
Trail class2, moderately developed; 4, highly developed
Typesnow trail
Surfacenative material
Typical grade12-20 percent
Typical tread width18-24 inches
Motor vehiclesOpen to at least one motorized use
AccessibilityNot evaluated
National designationNational Recreation Trail or other national designation
Trail numbers900
ForestCuster Gallatin National Forest (unit 0111)
StatesMontana
Detail publishedmanagement 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.

Allowed uses

SnowmobileAllowed 12/02 to 04/15 (month/day)
SnowshoeingAllowed year-round
Cross-country skiingAllowed 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

No season published · listed none
0 mi

Distance is from the point to the nearest part of the trail line. Season text is what the forest wrote and is often a season name rather than a date. The recreation page link goes to the Forest Service site, which may redirect to the forest's recreation index.

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

  • Prescribed
    Lonesome Wood Rx Unit 31B

    47 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 North (snowmo) Trail?

65.5 miles, the sum of the 6 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 North (snowmo) Trail?

snowmobile, snowshoeing and cross-country skiing. The trail is open to at least one motorized use. Some uses are seasonal. The allowed uses section lists the dates.

Source: Forest Service trail layer

Where does the Big Sky North (snowmo) Trail start?

The line begins at 45.5309, -111.1354 and ends at 45.1015, -111.2190. The nearest recorded trailhead is Buffalo Horn Trailhead, 0 miles from the line. The record does not say which end is the usual start.

Source: Forest Service trail layer

Is the Big Sky North (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 North (snowmo) Trail?

Little Bear Cabin (0.2 mi), Spire Rock Campground (0.5 mi) and Spire Rock Group Campground (0.5 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 North (snowmo) Trail?

Trail class 2 to 4, which the Forest Service describes as moderately developed to highly 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 North (snowmo) Trail?

The typical grade is 12-20 percent. The typical tread is 18-24 inches wide.

Source: Forest Service trail layer

Is the Big Sky North (snowmo) Trail a national trail?

Yes. The record marks it as a National Recreation Trail.

Source: Forest Service trail layer

Who manages the Big Sky North (snowmo) Trail?

Custer Gallatin National Forest, Forest Service unit 0111. The trail is in Montana.

Source: Custer Gallatin National Forest official page

Is there a fire near the Big Sky North (snowmo) Trail?

1 active incident within 50 miles of the trail midpoint as of 2026-09-17, the nearest Lonesome Wood Rx Unit 31B at 47 miles. Check the forest's closure orders before you go.

Source: Fire nearby

Source

This page is built from 6 segments named BIG SKY NORTH (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 17, 2026. The methodology page explains how segments become trails.