The Big Snowy Mountains, Montana

The Big Snowy Mountains rise up from the prairie lands of central Montana around 15 miles south of Lewistown.

These mountains are a unique-looking range at the geographical center of the state. The elongated 8-mile stretch with elevations over the 8,000 feet mark is characterized by the sparse tree cover and deep canyons that make the Big Snowy Mountains distinct.

On top of that, they were formed largely from porous limestone, which resulted in several springs where some of the purest Montana water is reported to be found. These include Big Springs, which is also the main water supply for nearby Lewistown.

Deep, bowl-like canyons and sparse tree cover characterize the southern side of the island range of mountains, which is dryer than the other areas.

On the northern side, longer forested canyons with a gentler rise are more common. On the western side of the mountains, various caves formed from the limestone can be found.

Big Ice Cave is the largest and most well-known of all the caves and is a popular attraction in the area. And despite the seeming isolation of the mountains from the other ranges in the state, the range sits mostly on federally-managed land.

The public land areas in the Big Snowy Mountains are managed by the Lewis and Clark National Forest ranger stations at Harlowton and Stanford, and this is the entirety of the management along with the Big Snowy Mountains Wilderness Study Area.

Aside from the Crystal Lake area and the well-known caves, the Big Snowy Mountains actually receive low use compared to other mountain regions of Montana.

With this in mind, a 100,000-acre area was set aside within the vicinity of the mountains for the purpose of serving as a Wilderness Study Area. The high country mountain area is home to different eagle varieties, elk, moose, deer, goats, and bears.

It is evident that one of the underlying aspects of the region in terms of its managing to stay wild and undeveloped is the lack of any identifiable commercial resources like precious metals or timber.

big snowy mountains stats
Image: Forest Service Northern Region

Big Snowy Mountains Stats

  • Approximately  3,700 square miles
  • Highest Peak—8,681 feet (Greathouse Peak)
  • Accessible year-round

Recreation in the Big Snowy Mountains

The 100,000-acre wilderness study area is an ideal access point to ample opportunity for pursuits like hiking and backpacking, horseback riding, and other forms of quiet recreation that fit a vast mountain landscape right in the center of Montana’s plains.

Local residents, prairie dwellers, and visitors alike revel in the outlets here for fishing, climbing, hiking, and camping in the high country accessible via a short drive.

On the northern end of the mountain range sits the popular Crystal Lake, which can be accessed via Rock Creek Road along MT- 200 to the west of Lewistown.

This is the main access point from which you can jump on a few trails if you wish, including a few leading to ice caves like Devil’s Chute.

You can also get to the Big Ice Cave via another path from here, and another 3.5-mile route leads up the East Fork of Rock Creek, culminating in some impressive views of Crystal Cascades, a 100-feet high stepped waterfall.

Big Ice Cave

The biggest and most well-known of the limestone caves in the mountains is Big Ice Cave. Situated just under the top ridge, the huge cave maintains cool temperatures year-round due to a heavily compacted icy snowdrift.

This amazing cave with its more than 100-feet long, sloping areas can be accessed from the south side near Neil Creek.


Image: Forest Service Northern Region

The Crystal Lake Campground is set at 5,700 feet and features various recreation areas and options. It is nestled in the basin of Crystal Lake, and this group site offers great access to various trails like those to the ice caves as well as the lake, which offers opportunities for swimming, fishing, and canoeing.

There are a few trees around the campsite but not enough to offer much by way of shade. Amenities include platforms, fire rings, picnic tables, vault toilets, and drinking water.

Big Snowy Mountains Backcountry Drive

This backcountry drive covers a route of seventy-seven miles and runs along the eastern and southern base regions of the Big Snowy Mountains.

The roads are mainly gravel and stretch between Lewistown and Judith Gap. The route features some outstanding views of the mountains, as well as East Fork Dam and Reservoir and a few remote areas of the region. This is actually a little-used route with little traffic that offers some excellent views of this part of the state.

The drive starts out in Lewistown along Highway 238–also known as East Fork Road—and only the first 10 miles or so are paved until the route reaches East Fork Dam and East Fork Reservoir. There is a campground at East Fork Reservoir which is the only developed one along the entire drive.

The scenic drive takes in all kinds of different scenery including fields and forest and reaches the road junction with East Red Hill Road forty-five miles from Lewistown.

From here you continue heading toward Judith Gap, turning right at the junction and then taking another right on Judith Gap Road in a western direction. The route runs through picturesque grassland prairies where the Big Snowy Mountains rise up abruptly.

When the scenic drive is close to Judith Gap the road improves and the drive ends at the junction with US Highway 191 in Judith Gap.


Crystal Lake is a 45-acre body of water at elevations over 6,000 feet. It is popular for fishing and hiking and the lake contains primarily rainbow trout that are usually stocked, although there are reports of a variety of other fish being caught such as smallmouth bass and white perch.

Big Spring Creek in Lewistown is one of the largest spring-fed streams in Montana. Its source is less than 10 miles away near the state’s Big Springs Trout Hatchery, and it runs in a north-western direction between the Big Snowy and the Judith Mountains, flowing into the Judith River west of Brooks.

At the head of the creek is a large spring surrounded by a park and a wildlife viewing area.

The fresh, clean, and cold water flows alongside grazing fields on US 191 and passes through Lewistown, while above the town sits Big Spring Creek.

This is an area considered by many anglers the primary trout stream in central Montana and thus can get quite busy during certain times of the year. Along with the brook trout and brown trout, the creek is known to contain other species like lake chub, long-nosed suckers, mottled sculpin, and common carp.

East Fork Reservoir was created from the East Fork Dam, and it has a small recreation area around it. The dam and reservoir were originally built for flood control along the East Fork Big Springs Creek but these days serve as another popular fishing and recreation spot close to Lewistown.

Hiking Trails in the Big Snowy Mountains

hiking trailst
Image: Forest Service Northern Region

Towards the east side of the Big Snowy Mountains, you can access trails such as the Half Moon Creek Trail, which approaches the mountains’ divide from the north.

Then the Swimming Woman Canyon Trail reaches it from the southern flank—and both of these byways meet near Greathouse Peak and just west of the second-highest peak Old Baldy.

A couple of other worthwhile routes are the Cottonwood Creek Trail, which follows the East Fork of Cottonwood Creek to Greathouse Peak, as well as the Old Baldy Ridge Route from the direction of its eastern slopes.

Crystal Lake Loop Trail

This is a challenging, 5-mile route that gains 2,200 feet in elevation. Gaining the crest rewards hikers with panoramic views opening up and out in all directions.

There are several approaches that allow access along the crest of the mountains along with a few small caves.

Ice Caves Loop

This is a 12-mile loop trail that is generally considered a challenging route. It takes almost 6 hours for most hikers to complete this trail, which is not an easy trail by any means but is worth the effort for the rewarding views.

The trail is easy-going in many parts except for right around the ice caves, where you will find the must-see Devil’s Chute.

Crystal Cascades via Ice Caves Trailhead

This is a 9-mile out & back trail generally considered a challenging route. It takes most people 4.5 hours to finish. This is a multi-purpose trail, although not overly–populated. The trail is well-maintained with plenty of elevation gain and descent.

Dogs are allowed and may be off-leash in some areas on this difficult hike which includes caves and views.

Grandview Trail

This is another trail with a steep gradient climbing up from Crystal Lake. The route covers 3.5 miles, and eventually, you come to a vista known as Grandview Point, which has some amazing views as you might imagine from the name.

The trail gains about 1,000 feet in elevation and offers excellent views of the surrounding region the whole way. If you want more elevation and you fancy tackling yet higher peaks, you can continue on the trail to the summit of West Peak.

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