RV route guide
Going-to-the-Sun Road — Glacier NP, Montana
The most-restricted famous-RV road in the US. A 21-foot length limit, a vehicle reservation system, and a 50-mile alpine crossing engineered in the 1930s.
Going-to-the-Sun Road traverses Glacier National Park from West Glacier to St. Mary, 50 miles over Logan Pass at 6,646 feet. It is on every road-trip bucket list. It is also the most restrictive famous-byway in the US National Park system: vehicles over 21 feet long or 8 feet wide are prohibited beyond Avalanche Creek on the west and Sun Point on the east. The reservation system was tightened in 2024. If you are travelling in any RV larger than a Class B campervan, you cannot drive this road in your rig.
Can I drive Going-to-the-Sun Road in an RV?
Only if your RV is under 21 feet long, under 8 feet wide, and under 10 feet tall. That excludes essentially all Class A motorhomes, all Class C motorhomes, all fifth-wheels, and most travel trailers. Class B campervans under 21 feet (Ford Transit-based, Mercedes Sprinter-based) qualify and are the only RV class realistically permitted. For larger rigs, the alternative is US-2 around the south boundary of Glacier (Marias Pass), about 60 miles longer but RV-friendly. You can also park the rig at Apgar or St. Mary and ride the free Glacier shuttle across.
- 21 ft length limit, 8 ft width limit, 10 ft height limit
- Reservation required late May to mid-September
- Class B only — all other RV classes prohibited
- Detour: US-2 around south boundary (60 mi longer)
- Glacier shuttle alternative — park rig at Apgar or St. Mary
At a glance
Route facts worth checking before you roll out
Conservative, source-minded numbers for planning — always confirm against current conditions and state DOT 511 before you depart.
Distance
50 mi
West Glacier to St. Mary, end to end
Drive time
2–4 hr
1 day
Elevation
3,200–6,646 ft
RV compatibility
Small RV only (Class B / van)
Max length 21 ft
Best season
Early July through mid-September. Logan Pass opens late June to early July, typically late opening due to snow. Closes early to mid-October. The road is closed to vehicles October through May.
Cell coverage. No reliable cell service along the road. Verizon has some coverage at Logan Pass visitor center; AT&T similar. T-Mobile minimal. Plan as if offline.
Elevation profile
From 3,200 ft at West Glacier climbing to 6,646 ft at Logan Pass, descending to 4,500 ft at St. Mary.
Vehicle restrictions
- 21-foot length limit including bumper, hitch, bike rack — measured at the longest extent
- 8-foot width limit excludes most travel trailers
- 10-foot height limit due to tunnel clearance
- Vehicle reservation required May 24 to Sep 8 (2026 window — verify on NPS Glacier site)
- Bicycle traffic restricted to early morning + after 4 p.m. mid-June through Labor Day
Why the restrictions exist
Going-to-the-Sun Road was completed in 1932. The road was carved into the cliff face of the Garden Wall by Civilian Conservation Corps workers using single-jack drilling and limited blasting. The lanes are narrow because the road is narrow because the cliff is narrow. There is no widening it without destroying the historical engineering that the road is famous for.
The width and height restrictions exist because the lower west-side switchbacks have rock overhangs. The length restriction exists because the hairpin switchback radii cannot accommodate articulated vehicles. The reservation system exists because Glacier's annual visitation has tripled since 2010 and Logan Pass parking simply cannot handle current demand without rationing.
GTSR vehicle restrictions vs. other restricted NPS roads
| Criterion | Going-to-the-Sun Road (Glacier) | Tioga Pass (Yosemite) |
|---|---|---|
| Length limit | 21 ft | No formal limit |
| Width limit | 8 ft | No formal limit |
| Reservation required | Yes May-Sep | No (entrance reservation may apply) |
| Steepest grade | 8% sustained west of Logan | 9% sustained west of Tioga |
| Snow window | Open early July to mid-October | Open late May to early November |
| RV-friendly assessment | Class B only | Most RVs handle with care |
Real warnings
Do not attempt to fake the 21-foot limit
Park rangers measure at the Avalanche and Sun Point checkpoints. Vehicles measured over 21 feet are turned back, no exceptions, including bike racks and hitches.
dangerLogan Pass parking fills by 7 a.m. in summer
If you must drive instead of shuttle, plan an early start. Apgar Visitor Center parking similarly fills by 9 a.m.
cautionWeather can close the road mid-summer
Snow squalls at Logan Pass close the road occasionally even in July. Check status before driving.
cautionBear country
Grizzly and black bears active. Keep food in vehicles. Carry bear spray on any hike from the road. Park-issued reminders on bear safety apply.
cautionWildlife jams cause backups
A single bear or mountain-goat sighting can stop traffic for 30+ minutes. Pull over safely; do not park in the lane.
info
Alternative routes for larger RVs
US-2 (Marias Pass detour)
Around the southern boundary of Glacier. About 60 miles longer than driving GTSR. RV-friendly, 5,200 ft summit. Connects East Glacier to West Glacier. The de facto big-rig route.
Park RV at Apgar Village, take Glacier shuttle
Free shuttle traverses GTSR end-to-end during operating season. Apgar campground has limited overnight RV sites. Day-use parking fills early.
Many Glacier (east side, separate entry)
Many Glacier road is RV-friendly to Many Glacier campground. Separate entrance from St. Mary. Worth a side trip even if you cannot drive GTSR.
Two Medicine (south of East Glacier)
Two Medicine road accommodates RVs up to 25 ft. Lake views, less crowded than Logan Pass.
Polebridge / North Fork
Unpaved road into the remote north of Glacier. Not RV-friendly. Suited only to high-clearance vehicles.
What NPS Glacier National Park doesn't tell you
The NPS Glacier site states the vehicle restrictions clearly but does not explain to RV renters how few rigs qualify. The reality is that the typical RV rental — a 25-ft Class C, a 30-ft Class A, or even a 22-ft camper trailer behind a Suburban — does not meet the limit. Rental customers learn this at the gate.
What NPS does not communicate is how good the alternatives are. The Glacier shuttle is genuinely excellent: 30-minute interval, free, runs Apgar to St. Mary in about two hours each way. Many seasoned RV travelers prefer the shuttle to driving GTSR — you can see the views without the white-knuckle driving.
The third underdiscussed point is US-2. Marias Pass on US-2 is itself a beautiful drive over the Continental Divide. It is the historic Great Northern Railway grade. RV travelers redirected to US-2 often report enjoying it more than they would have enjoyed GTSR.
Frequently asked questions
- What time does the reservation start?
- Vehicle reservations for Going-to-the-Sun Road in 2026 are required for entries between 7 a.m. and 3 p.m. Before 7 a.m. and after 3 p.m. no reservation required (just park entrance fee). Booking opens 4 months in advance plus a next-day window. Check the NPS Glacier reservation page for current dates.
- How do I measure my RV length?
- Bumper to bumper, including bike racks, hitches, tow tongues, anything that extends. Park rangers measure at the checkpoint. A 22-ft Class B with a bike rack measures over 22 ft and will be turned back. Remove appendages before approaching the checkpoint.
- Can I tow my car behind a Class B?
- No vehicle combinations over 21 feet total length on Going-to-the-Sun Road. A Class B plus a towed vehicle exceeds the limit.
- What if I have a reservation but the road is closed for weather?
- Refund issued automatically by Recreation.gov. Rebook for a later date if your trip allows. NPS does not pre-announce weather closures.
- Is the road open year-round?
- No. Going-to-the-Sun Road is closed October through May. The western section to Avalanche Creek and the eastern section to Rising Sun may be open longer but the central alpine section is annual winter closure.
Authoritative sources
Verify current conditions with state DOT 511 systems before departure. RV restrictions may change. Weather may close roads.
Planning an RV trip along Going-to-the-Sun Road?
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