West Yellowstone to Keystone: Road Trip Guide

The route from West Yellowstone, MT to Keystone, SD spans roughly 460 miles, crossing the Continental Divide twice and passing through the heart of the Greater Yellowstone Ecosystem before descending into the Black Hills. This drive is a study in contrasts: from geothermal basins and alpine meadows to high plains and granite peaks.

The journey begins in the shadow of the Madison Plateau, where the Madison River carves a path through volcanic rock. As you head east on US-20/US-191, you'll soon enter Yellowstone National Park via the West Entrance, the busiest of the park's five gates, handling over 1.5 million visitors annually. The park's geothermal features, like the famous Old Faithful geyser, are a direct result of the Yellowstone hotspot, a mantle plume that has fueled volcanic activity for millions of years.

After Yellowstone, the route continues through the Shoshone National Forest and the Bighorn Basin, a vast semiarid region rich in dinosaur fossils. The final stretch into South Dakota traverses the Wyoming High Plains before arriving in the Black Hills, a dome of eroded granite and limestone that rises dramatically from the prairie.

This guide aims to provide you with essential information on road conditions, fuel stops, and the best points of interest along the way, ensuring a memorable and safe journey.

Climatic conditions and route aesthetics: Summer daytime highs range from 70°F in Yellowstone to 90°F in the high plains, with afternoon thunderstorms common in July. Nighttime lows can dip into the 40s in the mountains. Winter brings heavy snow; the route is often closed due to winter storms. In fall, expect golden aspens in the Bighorns and clear skies in the Black Hills.

Infrastructure safety and road quality: The Yellowstone sections have limited shoulders and guardrails; watch for hairpin turns near the Golden Gate. Outside the park, roads are rural and may have potholes. I-90 is safe but can be winding in the Black Hills, with deer crossings. Always carry water and a spare tire; cell coverage is patchy, so download offline maps.

Family and child suitability: The drive is suitable for kids, with plenty of bathroom breaks and educational stops. The dinosaurs in Cody at the Draper Natural History Museum fascinate young ones. In Keystone, the Presidential Trail at Mount Rushmore is stroller-friendly but has stairs. Also, plan for the 'Gooseberry Falls' detour if time allows.

Pet-friendly framework: Most national forest campgrounds allow pets on leash, but Yellowstone requires pets to be leashed at all times and prohibits them on boardwalks and trailheads due to thermal dangers. In Keystone, the Mount Rushmore memorial welcomes pets on a leashed in designated areas, but not inside the buildings.

Hidden off-route spots: Just west of Buffalo, the 'Ten Sleep Canyon' offers a narrow gorge with hiking and rock climbing. In the Black Hills, the 'Needles Highway' is a dramatic, twisting road through granite spires, but is not suitable for large RVs (length limit 30 feet). Another gem is the 'Sylvan Lake' area, ideal for a picnic.

Fatigue management and rest zones: Rest areas are frequent on I-90, but the first leg on US-20 lacks many pullouts. Stretch at the Wapiti Ranger Station near Yellowstone's east gate, the Canyon Village Overlook, and in Buffalo at the hub. If fatigue sets in, pull over at a well-lit rest area and take a quick nap.

To discover more secrets: how to find the best stops and hidden gems between cities.

How long to drive West Yellowstone, MT to Keystone, SD: Plan on 8–10 hours of pure driving time, but with stops and sightseeing, expect a full day or an overnight trip. The most direct route follows US-20 East through Yellowstone, then US-14/US-16 East via Cody and Greybull, and finally I-90 East to exit 46 for US-16 to Keystone. An alternative is to take US-14 through the Bighorn Mountains, which is more scenic but adds about an hour.

Fuel and route economics: Gas stations are sparse east of Cody, so fill up whenever you have the chance. In Yellowstone, gas is available at Canyon, Fishing Bridge, Grant Village, and Old Faithful, but prices are typically 15-20% higher than in towns like Cody or Buffalo. Expect to pay around $3.50-4.00 per gallon. Overall, budget $80-120 for fuel for the trip.

Road quality: The roads within Yellowstone are well-maintained but narrow in places, with wildlife crossings frequent. Outside the park, US-20 and US-16 are two-lane highways with decent shoulders. I-90 is in excellent condition, with a 70 mph speed limit in Wyoming and 80 mph in South Dakota. However, winter weather can cause closures; check local advisories.

• Major rest stops: Yellowstone West Entrance (visitor center), Cody (Walmart, 2 blocks), Buffalo (Walmart, off I-25), and in Keystone right on Main Street.
• Nearby commercial zones: Cody has a full Walmart, while Buffalo has a Safeway and fast food options.
• Cellular coverage: Limited in Yellowstone and mountainous areas; AT&T and Verizon have dead zones.

Best stops West Yellowstone, MT to Keystone, SD include the Grand Canyon of the Yellowstone, where you can hike to Artist Point for a view of the Lower Falls plunging 308 feet. Just outside the park, the Buffalo Bill Center of the West in Cody showcases Western art and firearms history in a striking modern building. Further east, the Medicine Wheel in the Bighorn National Forest is a sacred Native American site on a remote mountain ridge, accessible by a short hike from the Burgess Junction.

UNESCO World Heritage Sites: Yellowstone National Park is one of the few World Heritage Sites on the route; it was honored in 1978. The park is renowned for its geothermal features, including over 10,000 hot springs, geysers, and mudpots, and is home to the largest concentration of mammals in the continental US.

Things to do between West Yellowstone, MT and Keystone, SD: In Yellowstone, consider a guided wildlife tour (Bison, elk, wolves; $50-100 per person). In Cody, the nightly rodeo from June through August is a family favorite. The Devil's Tower National Monument, just a short detour off I-90, is a 1200-foot igneous rock formation and the first national monument, established in 1906.

Local commerce and culture: Cody's downtown is a tourist hub with galleries and gift shops, while Sheridan, WY, offers a taste of Western heritage with the King Ropes headquarters and a historic Main Street. In Keystone, the focus is on Mount Rushmore, but you'll find local artisans selling jewelry and woodwork near the monument.