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MONTANA 4x4 TRAIL GUIDE · MT-0051

Main Fork Rock Creek Road (FS 2421) to Glacier Lake

Forest Road 2421, Glacier Lake Road · Beartooth Ranger District · south of Red Lodge, Montana
2/10AGF Difficulty · Easy · estimate; no record of AGF driving it
8.6 MIOne way to the trailhead (FS MVUM data 8.626; FS directions 0.9 + 7.7)
HIGHWAY-LEGAL ONLYYearlong (FS MVUM data, Oct. 12, 2026); winter order Dec. 1–June 15 in 2025–26
USFSBeartooth Ranger District
HIGHWAY-LEGAL VEHICLES ONLY. A WINTER ORDER CLOSED NEARLY THE WHOLE ROAD FROM DEC. 1, 2025 TO JUNE 15, 2026, AND A SIMILAR ORDER MAY BE REISSUED. FS 2421 is "Roads open to highway legal vehicles only, Yearlong" (live FS MVUM data, read Oct. 12, 2026); non-street-legal ATVs, UTVs and dirt bikes are not allowed. Winter order 01-11-82-26-01 prohibited wheeled motor vehicles on FS 2421 "from the Junction with NFSR #2004 (Hellroaring Road)" to "the roads terminus, including all spur roads connected." It read: "This Order shall be in effect from December 1, 2025, at 8:00 am through June 15, 2026 at 8:00 am, unless rescinded." The Hellroaring junction is about 0.9 mile from US-212, so the order covered nearly the whole route. It has expired; whether a similar order will start Dec. 1, 2026: verify on the Custer Gallatin alerts page. The road is not plowed: the M-K Campground page says, "In the off-season there are no services, the campground is not maintained, and roads are not plowed." The Forest Service says, "Please be advised that the Main Fork Rock Creek Rd is rocky with potholes." and "High clearance vehicles are advised." Upper end: the road end is just inside Wyoming: Census boundary data and BLM land-status data both place the road end (45.0030, -109.5136) in Wyoming, and an onX report (secondary) says, "Open until the third gate just inside Wyoming." Expect gates on the upper road. Which forest manages the upper ~2.6 miles: verify with the Beartooth Ranger District. Motor vehicles stop at the road end; the trail beyond is not open to vehicles (wilderness boundary location: verify). The Forest Service warns that marmots have damaged cars parked at the trailhead in past years (paraphrase). NPS (updated Oct. 9, 2026) says the Beartooth Highway over the pass is "Scheduled to close for the season Monday, October 12 and, depending on conditions, may not reopen until next spring." The FS 2421 turnoff is likely below the Montana-side winter gate (2013 report): verify with MDT (511). FS 2421's vehicle class comes from the Forest Service's live MVUM data (EDW, read Oct. 12, 2026); check the 2026 MVUM before you go. Official closures, posted signs and private property override this guide. Call the Beartooth Ranger District (406-446-2103) before you go, and read Know Before You Go.
NO RECORD OF AGF DRIVING MAIN FORK ROCK CREEK ROAD. THIS 2/10 IS AN ESTIMATE FROM OFFICIAL AND SECONDARY SOURCES. No record of AGF driving this route. AGF's GPS archive (274 tracks) has no track on the road between M-K Campground and the road end (checked Oct. 12, 2026). Everything here comes from official sources, plus clearly labeled secondary sources. AGF will re-rate it after an AGF run.
WHAT THIS GUIDE COVERS

US-212 to the Glacier Lake Trailhead

Main Fork Rock Creek Road (FS 2421) from US-212 past the Rock Creek campgrounds and M-K Campground to the road end at the Glacier Lake trailhead, and back the same way: about 8.6 miles one way (FS MVUM data 8.626; FS directions 0.9 + 7.7), about 17.2 miles round trip. Pavement for the first 0.89 mile, then gravel to MP 3.618 and native surface beyond (FS MVUM data). The road is also called Glacier Lake Road #2421 (FS alerts).

NOT INCLUDED: Hellroaring Road (FS 2004; its own guide), Glacier Lake Trail #3 and anything beyond the road end, spur roads, and any travel past a closed gate.
WHY 2/10

Easy · Rocky, Potholed Forest Road

NO RECORD OF AGF DRIVING THIS ROUTE: the 2/10 is AGF's estimate, not an AGF run. AGF rates a trail by its hardest unavoidable obstacle in normal dry conditions. Here that is the rocky, potholed upper road: the Forest Service says it "is rocky with potholes" and that "High clearance vehicles are advised." onX (secondary) rates it 2 and says, "Hills with lose rocks not very steep" [sic]. No technical obstacle is documented. Snow, ice, washouts and winter orders are condition changes, not part of the base rating.

Rock
2/5
Mud
2/5
Water
1/5
Exposure
2/5
Snow
4/5
Pinstriping
1/5

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

ROUTE & MAP

Getting There

Forest Service directions from the Beartooth Ranger District office (6811 Hwy 212, Red Lodge): "Drive south on US Hwy 212 towards Cooke City for 10.9 miles." "Turn right onto the Main Fork Rock Creek Rd (FR #2421)." Drive about 0.9 mile past the Parkside, Greenough and Limberpine campgrounds and turn left near Limberpine Campground "to continue on the Main Fork Rock Creek Rd" (FS); Hellroaring Road (FS 2004) bears right. Signs: verify. M-K Campground is 2.6 miles farther ("Drive 2.6 miles to the campground."). "Drive 7.7 miles to the trailhead." Return the same way.

LOADING MAP…
Glacier Lake Trail #3 (FS) →Custer Gallatin alerts →ROUTE FILE: not published yet

The pin marks M-K Campground (Forest Service page coordinate; not field-checked), partway up the road. The road end is at about 45.0030, -109.5136 (live FS MVUM data), just inside Wyoming (Census boundary data). No downloadable track is published.

VEHICLE FIT

Rig Requirements

Stock 4x4
Yes
High clearance
Recommended
Tires
30-inch minimum
Rear locker
No
Front locker
No
Winch
Optional
Full-size
Yes, with caution on the upper road (AGF record)
Body damage
Low risk

A stock 4x4 or SUV is appropriate in normal dry conditions; the Forest Service advises high clearance. Carry quality A/T tires, a full-size spare, rated recovery points, offline maps and basic recovery gear (AGF record). Lockers and a winch are not baseline. Full-size and long-wheelbase rigs are generally fine, but the road gets rougher and narrower beyond M-K Campground; stage large campers and trailers lower (AGF record). Highway-legal vehicles only.

TRIP PLANNING

Know Before You Go

Season
Highway-legal vehicles yearlong (FS MVUM data), except under winter orders (Dec. 1, 2025–June 15, 2026 last season; 2026–27: verify); not plowed. M-K page: "Access is snow dependent."
Vehicles
Highway-legal only (FS MVUM data, Oct. 12, 2026; check the 2026 MVUM)
Typical trip
Half day plus hiking (AGF record estimate)
Camping
M-K Campground and the lower Rock Creek campgrounds (FS); off-season: no services
Trailers
Stage on the lower road or at campgrounds (AGF record)
Turnaround
At the trailhead and established pullouts (AGF record)
  • Hunting season: Montana's general deer and elk season runs Oct. 24–Nov. 29, 2026 (FWP). Expect hunters, camps and parked vehicles; wear blaze orange outside the vehicle. Archery season runs to Oct. 18. A youth deer hunt runs Oct. 15–16 (FWP).
  • Grizzly country: Custer Gallatin food storage order 01-11-00-23-02 applies on the Gardiner and Beartooth Ranger Districts, Mar. 1–Dec. 1.
  • The only alert naming FS 2421 on the Custer Gallatin alerts page on Oct. 12, 2026 was the expired winter order (Beartooth fire danger Moderate). Recheck before you go, especially after Nov. 2026.
  • Contacts: Beartooth Ranger District (406-446-2103), 6811 Hwy 212, Red Lodge. For the upper end in Wyoming, the Shoshone NF Clarks Fork Ranger District (phone: verify).
SOURCES

Sources & Review

Last reviewed Oct. 12, 2026. No current order is listed, but FS 2421 is highway-legal only, a winter order closed nearly the whole road Dec. 1, 2025–June 15, 2026 and may be reissued, the road is not plowed, and the upper end is in Wyoming. There is no record of AGF driving Main Fork Rock Creek Road; the 2/10 is an estimate from official and secondary sources.

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.