Blue Lake 4x4 Trail near Big Timber, Montana | Trail Guide

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MONTANA 4x4 TRAIL GUIDE · MT-0026

Blue Lake

Independence ghost town · Main Boulder high country · south of Big Timber, Montana

4/10AGF Difficulty · Moderate

HIGHClearance required

20.8 MIOut & back (AGF record)

USFSCuster Gallatin NF

PASSABLE VIA A PERMITTED DETOUR. CONFIRM IT IS OPEN BEFORE YOU GO. Two bridges on the Main Boulder Road south of Box Canyon failed after the 2022 flood, and Park County closed the road to recreational vehicles in January 2024. As of September 2026 the Sweet Grass County Recreation Association had a legally permitted low-water crossing built about 2.2 miles south of Box Canyon around one of the failed bridges. AGF contacts have since driven the full route to Blue Lake, but AGF has not verified how the second failed bridge is passed. AGF has not seen a notice that Park County lifted its 2024 closure: confirm with Park County that recreational vehicles are allowed before you drive it. Bridge repairs are still pending (expected 2026–2027), a low-water crossing is only as good as the water level (AGF advice), and the road past Fourmile Bridge has potholes. Check current road and bridge status with Park County and the Custer Gallatin National Forest, use the current MVUM, and read Know Before You Go.

WHAT THIS GUIDE COVERS

High Country to Blue Lake

A remote high-country run south of Box Canyon, past the Independence mining ghost town, to the end of the motorized route about 200 yards short of Blue Lake. It is a full-day trip: the trail itself starts roughly 48 miles from Big Timber.

NOT INCLUDED: the long Main Boulder Road approach from Big Timber, side spurs, and the final walk to the lake. Motor vehicles stop where the motorized route ends.

WHY 4/10

Moderate · Low Range Useful

AGF rates a trail by its hardest unavoidable obstacle in normal dry conditions. Beyond the Main Boulder approach the high-country road is rocky, steep and bumpy, with several spots where low range helps and rough bridge or bypass areas. AGF drove the full route in August 2020. Snow, high water and mud can raise the difficulty a lot.

Rock

4/5

Mud

3/5

Water

4/5

Exposure

3/5

Snow

5/5

Pinstriping

4/5

Snow, mud, runoff, deadfall and fire are condition changes, not part of the base rating.

ROUTE & MAP

Getting There

From Big Timber, follow the Main Boulder Road south to the Box Canyon area (legacy route sources put the trailhead roughly 48 miles from Big Timber). The permitted low-water crossing is about 2.2 miles south of Box Canyon. Independence is about 5 miles past the Box Canyon Trailhead, and the road continues about 4 more miles toward Blue Lake (Billings Gazette, 2025). The motorized route ends about 200 yards short of the lake.

LOADING MAP…

Custer Gallatin alerts →ROUTE FILE: not published yet

The pin marks Blue Lake. No downloadable track is published: AGF's 2020 recording predates the 2026 low-water crossing, so it would not show the current detour.

VEHICLE FIT

Rig Requirements

Stock 4x4: Yes
High clearance: Required
Tires: 31-inch minimum
Rear locker: Recommended
Front locker: No
Winch: Recommended
Full-size: Limited
Body damage: Moderate risk

Narrow primitive road, brush, rocks and limited passing and turnaround space make long or wide full-size rigs a poor fit. Carry a saw, full-size spare, rated recovery points, radio, offline maps and extra fuel.

TRIP PLANNING

Know Before You Go

Season: Short high-country summer season; snow, runoff and bridge dependent
Seasonal restrictions: Verify on the current MVUM
Typical trip: Full day
Camping: Yes
Trailer parking: Yes
Turnaround: Limited

This is grizzly country. Check the Custer Gallatin alerts page for the current food storage order.
Check the low-water crossing level before committing; do not drive a crossing you cannot see the bottom of.
Stay on the designated route. Private land and county road sections mix along the Main Boulder corridor.

PHOTOS

On the Trail

Whitewater falls in a rocky gorge with a footbridge above — Falls on the approach

Custer Gallatin National Forest sign for the Independence Area Trailhead — Independence Area Trailhead

Blue Lake reflecting snow-streaked peaks under a blue sky — Blue Lake

FJ Cruiser on a rocky track with jagged peaks behind — Rocky two-track near treeline

Collapsed rusted mining structure in a high meadow — Mining ruins along the route. Look, don't touch.

View over the hood of a rig ahead climbing a rocky, rutted section — Rocky section, from the driver's seat

Photos: Aaron Thies / AGF, Aug 1–2, 2020. They show the route on that trip, not current road or bridge conditions.

SOURCES

Sources & Review

AGF: A Bypass for Blue Lake, and Morrison's Back (Sept. 18, 2026; permitted low-water crossing)
Billings Gazette via Montana Outdoor: A perfect storm of problems for popular Boulder River road (June 2025; Park County closure, bridges, distances to Independence and Blue Lake)
Livingston Enterprise: 'Raise the Boulder bridges' (Sept. 2025; collapsed bridges south of Box Canyon)
Livingston Enterprise: Park County seeks federal funding for sheriff's office, bridges (2026; bridge funding)
Custer Gallatin National Forest alerts (current orders and closures)
Montana FWP Blue Lake access description (cited in the AGF trail record; places the lake about 200 yards past the end of the motorized route)

Last reviewed Oct. 8, 2026. AGF contacts report the full route passable via the low-water crossing. Whether Park County has lifted its 2024 closure, the current water level and road condition are not verified. AGF last drove the full route on Aug. 1, 2020.

AGF ratings describe normal, dry-condition difficulty. They do not mean a route is legal, open or passable today. Spot something out of date? Use the Contact page.