Yellowstone Grand Loop Road

Mammoth Hot Springs to Mammoth Hot Springs

Greater Yellowstone · Wyoming · United States

Key measurements

Distance

149.7 miles

Elevation gain

9,050 ft

Elevation loss

9,072 ft

High point

8,892 ft

Low point

5,869 ft

Net change

-12 ft (6,336 ft to 6,323 ft)

Surface

Paved

Route type

loop

Route Overview

Yellowstone Grand Loop Road forms a 149.7-mile circuit through Yellowstone National Park, linking Mammoth Hot Springs, Norris, the Firehole geyser basins, Yellowstone Lake, the Grand Canyon of the Yellowstone, and Dunraven Pass. The route crosses more than 3,000 feet of elevation change, from the dry northern hills to nearly 8,900 feet at Dunraven Pass, while moving through hydrothermal basins, lodgepole pine forest, broad valleys, lake shore, and volcanic canyon country.

The physical landscape shifts rapidly along the loop: lodgepole pine forests and bubbling thermal basins give way to vast high-altitude lakeshores, wide glacial river valleys, and stark, carved basalt canyons.

Key Segments & Geographic Transitions

Northern Terraces and Obsidian Corridor — Miles 0.0–13.8

Beginning in the northern reaches of the park, the road climbs out of dry sagebrush hills into dense lodgepole forests, passing ancient volcanic flows and the dark volcanic glass of Obsidian Cliff. The corridor follows Roaring Mountain and small alpine lakes as it descends toward the thermal corridor of Norris Geyser Basin, where geothermal steam often hangs over the roadway.

Geyser Basins and Firehole Valley — Miles 14.3–38.3

Carving south through the caldera floor, the route follows the Firehole River into the park’s dense concentration of active hydrothermal features. Steam vents, mudpots, and silica-rich runoff channels line the road as it weaves past Lower, Mid, and Upper Geyser Basins. The terrain features moderate sweeps through pine flats, crossing the Continental Divide before reaching the elevated shores of Yellowstone Lake.

Lake Shoreline and Hayden Valley — Miles 44.9–96.8

Tracking along the western and northern edge of Yellowstone Lake—the largest high-elevation lake in North America—the road provides open water views across to the Absaroka Range. Leaving the water, the route follows the Yellowstone River north through Hayden Valley, a broad glacial basin framed by rolling meadows. The segment culminates at the Grand Canyon of the Yellowstone near Canyon Village, where the river plunges into a deep, hydrothermally carved gorge of yellow and rust-colored rhyolite.

Dunraven Pass and Northern Range — Miles 97.6–148.9

The final major quarter ascends the shoulders of Mount Washburn to cross Dunraven Pass at 8,892 feet, the highest point on the circuit. This subalpine stretch features exposed mountainsides and panoramic alpine vistas before dropping sharply into the Tower-Roosevelt district. Passing basalt columns, overhanging cliffs, and Tower Fall, the route finishes by winding back along the northern park boundary through steep mountain drainages to complete the circuit.

Seasonal & Environmental Context

The Grand Loop operates on a staggered seasonal schedule, with lower-elevation sections typically opening in spring and the high Dunraven Pass section opening later as snow conditions allow. Most of the loop closes to regular vehicle traffic by the end of October, with exact dates varying by segment and weather.

At elevations consistently above 7,000 feet, rapid weather shifts are standard. Warm afternoon sun can quickly turn into localized rain, hail, or sudden snow squalls, even during midsummer. Early morning temperatures frequently drop near freezing in high basins, creating damp or icy patches in shaded turns. Sulfur fumes and steam from thermal features can occasionally drift across low-lying road sections.

Logistics & Services

Fuel and services are situated at major developed nodes around the loop, including Mammoth, Canyon Village, Fishing Bridge, Grant Village, and Old Faithful. However, stretches between these junctions run 25 to 50 miles without roadside infrastructure.

Cellular coverage is limited outside primary visitor hubs and vanishes entirely in mountain passes and deep valleys. Park speed limits range between 25 and 45 mph, enforced strictly due to heavy visitor traffic, tight turnouts, and frequent wildlife crossings.

Important Considerations

Wildlife Congestion: Bison, elk, bears, and pronghorn frequently occupy the roadway or graze immediately adjacent to the asphalt. Expect sudden stops, long delays ("bison jams"), and animals stepping into travel lanes without warning. * Pavement Surface: Thermal activity beneath the roadbed causes localized settling and frost-heaving. In hot summer weather, road bitumen near active thermal areas can soften. * Park Traffic: Heavy motorhome, tour bus, and rental vehicle traffic is common throughout the day. Turnouts are frequent but often congested near major geothermal features.