Sun Valley to Red Lodge: Epic Idaho-Montana Road Trip

On the morning of August 17, 1959, an earthquake near Hebgen Lake, just 20 miles northwest of West Yellowstone, permanently altered the landscape you'll traverse on this drive. The 7.3-magnitude quake caused a massive landslide that dammed the Madison River, creating Earthquake Lake. Today, the scar remains visible from US-287 as you approach the Montana-Idaho border. This geological event underscores the raw, dynamic forces that shaped the route from Sun Valley, ID to Red Lodge, MT.

This 400-mile journey (approximately 6.5 to 8 hours of pure driving time) is a masterclass in Rocky Mountain diversity. You'll climb from Sun Valley's arid high desert at 5,900 feet to the 8,600-foot Teton Pass, skirt the volcanic caldera of Yellowstone National Park, and descend into the timbered Beartooth foothills. The route uses US-20, US-191, and US-212—the latter forming part of the iconic Beartooth Highway. While the drive can be done in a single day, the density of attractions makes a multi-day trip far more rewarding.

Before you go, read our guide on how to find the best stops and hidden gems between cities. It will help you uncover the unexpected along this incredible corridor.

Route Snapshot

UNESCO World Heritage Sites

The route touches two UNESCO sites: Yellowstone National Park (World Heritage Site) and the nearby Waterton-Glacier International Peace Park (though Glacier is a detour). Yellowstone, established in 1872, contains half the world's active geysers. Key overlooks include the Grand Canyon of the Yellowstone (Artist Point) and the Hayden Valley for bison. Entry fee for Yellowstone: $35 per private vehicle (valid 7 days). If you're continuing to Grand Teton, consider the $70 Interagency Annual Pass.

• Yellowstone's geothermal basins (Midway, Upper) are 15–20 minutes off US-191 via park entrance at West Yellowstone.
• Boiling River: A natural hot spring soaking spot near Mammoth Hot Springs (clothed swim required).

Local Commerce & Culture

Sun Valley's first ski lift in 1936 made it America's first destination ski resort. Today, the Sun Valley Village offers high-end boutiques and the iconic Sun Valley Lodge. In contrast, the tiny town of Cooke City (pop. ~140) is a mining relic turned gateway to the Beartooth. For local crafts, stop at the Community Market in West Yellowstone (Wednesdays in summer) for huckleberry jam and hand-tied flies. The historic Red Lodge Saloon (circa 1915) still has original tin ceilings and serves locally brewed Red Lodge Ales.

Natural Landscapes & Attractions

The drive from Sun Valley climbs through the Targhee National Forest along US-20, offering distant views of the Teton Range. At mile 150 near Ashton, turn off on the Mesa Falls Scenic Byway to see the 114-foot Lower Mesa Falls. Continuing north, US-191 enters Yellowstone's west side, passing the 10,000-foot pitch of the Gallatin Range. After leaving West Yellowstone, US-212 climbs over the Beartooth Plateau—a 30-mile alpine tundra above treeline with glacial lakes and lingering snowfields. This is arguably the most scenic highway in America.

• Best photo spots: Teton Pass overlook (mile 90), Gibbon Falls (Yellowstone, mile 220), Beartooth Lake (mile 350).
• Wildlife: Grizzly bears in the Hayden Valley; bighorn sheep on the Beartooth.

Infrastructure Safety & Road Quality

US-191 from West Yellowstone to Bozeman is a major truck route and can be busy in summer. The Beartooth Highway (US-212) is a narrow, winding two-lane road with no guardrails in many sections. RVs over 30 feet are strongly discouraged. Cell service is absent from mile 250 (after West Yellowstone) until Red Lodge. Download offline maps. Carry a spare tire and emergency kit; the nearest auto repair is in West Yellowstone or Red Lodge.

• Road quality: Good pavement on US-20 and US-191; US-212 has frost heaves and gravel patches early season.
• Warnings: Bicyclists frequent the Beartooth in summer; share the road.

Family and Child Suitability

The route is family-friendly with many short, easy hikes. The Mesa Falls boardwalk is wheelchair stroller accessible. In Yellowstone, the Old Faithful area has paved paths and an education center. Kids will love the Grizzly & Wolf Discovery Center in West Yellowstone. For a longer stop, the Yellowstone IMAX theater shows wildlife documentaries. Car games like license plate bingo help on long stretches. For baby-changing and nursing, most visitor centers have clean facilities.

Pet-Friendly Framework

Pets are not allowed on Yellowstone's boardwalks or trails (thermal areas), but can stay in your vehicle at pullouts. They are allowed on paved paths in developed areas. Many lodges in West Yellowstone are pet-friendly (e.g., Kelly Inn West Yellowstone). On the Beartooth, dogs can hike in national forest lands but must be leashed. Plan stops at rest areas with shade; the altitude makes dehydration a risk. Carry extra water and a collapsible bowl.

Fatigue Management & Rest Zones

The long climbs and high altitude can cause driver fatigue. The most tiring section is the Beartooth Highway due to its constant 5 mph hairpin turns. Schedule stops every 2 hours. Ideal rest points: Sawtelle Peak overlook (mile 100), big pullout on US-287 near Quake Lake (mile 180), and the Cooke City rest area (mile 310). Caffeine is available at gas stations but no major truck stops until Red Lodge. Take a short walk at each break.

Culinary Infrastructure

Sun Valley upscale dining: the Pioneer Saloon for steaks. West Yellowstone mountain fare: the Wild West Pizzeria for huckleberry pizza. On the Beartooth, cook your own at the campgrounds. In Red Lodge, the Red Lodge Café for award-winning pies. Key local foods: trout, bison burgers, and huckleberry everything. For quick eats, Idaho Falls has national chains.

Hidden Off-Route Spots

Just 15 miles off US-20 near Ashton, the Warm River Springs offers a natural hot spring pool (free, no amenities). Near mile 270 on US-212, a short hike leads to the Lost Lake Trail, a quiet alpine lake without crowds. Just before Red Lodge, the Cooney Reservoir State Park has fishing and a sandy beach—a great place to cool off after the drive.

Fuel and Route Economics

Gas stations are sparse between Idaho Falls and West Yellowstone, and again from Cooke City to Red Lodge. Top off in Idaho Falls (mile 75), Ashton (mile 135), and West Yellowstone (mile 210). In Montana, the next reliable gas is in Cooke City (mile 310) and Red Lodge (mile 400). Expect fuel prices to be 10–20% higher in resort towns like Sun Valley and West Yellowstone. A sedan's fuel cost for the trip (assuming 25 MPG and $4/gallon) is approximately $64. For RVs, use lower MPG estimates.

• Sun Valley: premium fuel available at $4.50/gal.
• Idaho Falls: cheapest fuel on route, around $3.60/gal.
• Ashton: last cheap stop before Yellowstone; ~$3.80/gal.
• West Yellowstone: tourist pricing, $4.20–$4.50/gal.
• Cooke City: often above $4.50/gal.
• Red Lodge: moderate pricing, ~$4.00/gal.

Climatic Conditions & Route Aesthetics

The route is bookended by high mountain passes: Teton Pass (8,861 ft) and Beartooth Pass (10,947 ft). Both are prone to sudden snowstorms, even in July. The Beartooth Highway (US-212) typically opens from late May to mid-October, but check road conditions at 511 Idaho and 511 Montana. Summer daytime temps range from 70s in Sun Valley to 50s on the Beartooth summit. Late afternoon thunderstorms are common in July and August, especially near Yellowstone.

• Best aesthetic: Late September when aspen and cottonwoods turn gold in the valleys, and elk bugle in the meadows.
• Wildflower peak: Late June to early July on the Beartooth plateau.
• Winter closure: Beartooth Highway fully closed; only route is via I-90 and US-212 through Montana (longer, all-weather).