Twin Falls to Custer: Ultimate Road Trip Guide via I-84, US-20, I-25, US-16

This 670-mile journey from Twin Falls, Idaho to Custer, South Dakota crosses three states and four distinct eco-regions. The route traces the Snake River Plain, climbs into the Rocky Mountains, then descends onto the High Plains before rising again into the Black Hills. A little-known fact: the highway segment from Rawlins, WY to Lusk, WY (US-18/20) parallels the old Cheyenne-Deadwood stage route used during the 1870s gold rush.

Driving this route answers the question is it worth driving Twin Falls, ID to Custer, SD with a resounding yes. The landscapes range from volcanic lava fields to alpine meadows, from red desert to Ponderosa pine forests. The most efficient path combines I-84 east, US-20/US-26 through Wyoming, I-25 north, and US-16 into the Black Hills. Total drive time without stops is approximately 10 hours, but plan for 2-3 days to savor the sights.

For a deeper strategy on unearthing hidden gems along any route, check out our guide on how to find the best stops and hidden gems between cities.

Infrastructure safety: The most hazardous section is US-18/20 in Wyoming, which is a two-lane highway with high speed limits (65-70 mph) and minimal lighting. Watch for deer and antelope, especially at dawn/dusk. In the Black Hills, US-16 is winding and can be icy in winter. Cell service is spotty west of Rawlins and between Lusk and Newcastle. Download offline maps before departure.

Family and child suitability: Kid-friendly stops include the Shoshone Falls Park (playground, picnic areas), the Oregon Trail Ruts near Guernsey (interesting history), and the Mammoth Site in Hot Springs, SD (99 miles south of Custer). Custer itself has the 1880 Train (steam locomotive) and the Black Hills Playhouse. For educational value, the Wind Cave tour (above and below ground) is suitable for ages 6+.

Pet-friendly framework: Both Shoshone Falls and Custer State Park allow leashed pets. Many motels in Rawlins and Lusk accept pets with a fee. Rest areas along I-84 and I-25 have pet exercise areas. Be mindful of rattlesnakes in the Red Desert – keep dogs on trails.

Fatigue management: Best rest stops are the I-84 rest area near Heyburn (mile 182), the US-30 rest area in Little America, WY (free coffee and cookies), and the US-18/20 rest area near Lusk. For overnight stops, consider Rawlins (historic downtown) or Lusk (sleepy town). To break the trip, stay a night in Lusk and visit the Stagecoach Museum.

Hidden off-route spots: From Twin Falls, detour 15 minutes to Balanced Rock Park. Near Rawlins, take the Circuit Trail at the Continental Divide National Scenic Trail. From Lusk, drive 20 miles south to the Hat Creek Fossil Beds (free). Near Custer, hike the Black Elk Peak (highest point east of the Rockies) from Sylvan Lake.

Climatic conditions: Summer (June-August) is hot in Wyoming (90s F) and mild in the Black Hills (70s). Thunderstorms are common, especially in the afternoon. Winters are brutal: snow possible from October to April, with blizzards on the High Plains. The best seasons are late May and September, when temperatures are moderate and crowds thinner. Route aesthetics: the most photogenic stretch is US-16 from Newcastle to Custer, winding through the Black Hills with granite spires and ponderosa pine.

Fuel economy is a primary concern on this route because gas stations can be sparse in Wyoming. The longest gap without services is between Rawlins and Lusk (120 miles) on US-18/20. Always fill up in Twin Falls (multiple stations near I-84), then again in Rawlins. In Wyoming, stations in Sinclair, Medicine Bow, and Lusk are reliable. From Lusk to Custer, fuel is available in Newcastle, WY (60 miles) and then Custer itself.

Tolls: none on this route. Road quality varies: I-84 and I-25 are well-maintained interstates; US-20/26/287 are two-lane highways with some rough patches, especially in winter. The stretch from Lusk to Custer (US-18/85/16) is mostly good but can be narrow with sharp curves in the Black Hills. For those pondering how long to drive Twin Falls, ID to Custer, SD, the pure driving time is 9-10 hours, but factoring in stops, plan for 2-3 days.

Accommodation: book ahead in summer. Twin Falls has chain hotels; Rawlins offers budget motels; Lusk has a few historic inns; Custer requires reservations due to nearby Mount Rushmore traffic. Camping is abundant: Shoshone National Forest and Black Hills National Forest have numerous campgrounds.

The best stops Twin Falls, ID to Custer, SD include Shoshone Falls, often called the Niagara of the West (higher than Niagara). In Idaho, the Snake River Canyon offers dramatic views. As you cross into Wyoming, the landscape shifts to the Red Desert near Rawlins – a high-altitude desert with sagebrush and wild horses. The Oregon Buttes and the Continental Divide at South Pass are historic landmarks.

UNESCO World Heritage Sites: While none directly on route, Yellowstone National Park (to the west) is a UNESCO site. However, within a detour, you can visit the fossil sites of the John Day Fossil Beds (Oregon) or the newly designated “Serpent Mound” but those are far. Closer to Custer, Mount Rushmore is a National Memorial, not UNESCO. Wind Cave National Park (south of Custer) is a designated UNESCO Biosphere Reserve.

Local commerce and culture: Twin Falls is known for trout fishing and farming. Rawlins has a coal mining history. Lusk hosts the Wyoming State Fair. Custer is a tourist hub for gold rush history and Native American culture. Don’t miss the Crazy Horse Memorial and the Custer State Park buffalo herd. Local food specialties include Rocky Mountain oysters, bison burgers, and huckleberry treats in the Black Hills.