Sun Valley to Afton: Scenic Drive Through Idaho and Wyoming

The drive from Sun Valley, Idaho, to Afton, Wyoming, covers approximately 150 miles along US-20, US-26, and US-89, traversing the Snake River Plain and the Caribou-Targhee National Forest. This route crosses the Continental Divide at Teton Pass (elevation 8,431 feet), where the road narrows to two lanes with sharp curves. Historically, this corridor was used by Shoshone and Bannock tribes before becoming a key route for westward pioneers along the Oregon Trail. The drive typically takes 3.5 hours without stops, but plan for 5-6 hours to fully explore the attractions.

The route is generally safe, but caution is needed on US-89 near Star Valley where wildlife (elk, moose) frequently crosses. Speed limits are strictly enforced in small towns. For families, the Idaho Falls Zoo and the Museum of Idaho offer educational breaks. Pet-friendly stops include the Palisades Creek Trail (leashed dogs allowed) and picnic areas at Ririe Reservoir. Fatigue management rest zones include the rest area at milepost 30 on US-20 (eastbound) with tables and restrooms, and the Targhee Creek Picnic Area on US-89. For food, try the Swan Valley General Store for sandwiches and local huckleberry products. Culinary highlights: the Snake River Grill (Idaho Falls) for farm-to-table dishes, and the Afton Mercantile for Wyoming-style bison burgers.

• Family stops: Tautphaus Park Zoo (Idaho Falls), Lion’s Park playground (Swan Valley).
• Pet-friendly: Pettit Park in Idaho Falls (leash required), Palisades Reservoir dog-friendly shore.

The journey begins in the Sawtooth National Recreation Area near Sun Valley, with views of jagged peaks and the Big Wood River. As you head east, the terrain flattens into the Snake River Plain, a volcanic basalt plateau dotted with lava flows and sagebrush. Near Idaho Falls, the Snake River widens, offering riverfront parks and the Idaho Falls River Walk. Approaching the Wyoming border, the landscape rises into the Caribou-Targhee National Forest, with dense pine forests, alpine meadows, and glimpses of the Palisades Reservoir. Afton sits in Star Valley, a lush agricultural area known for its world’s largest elk antler arch—a 75-foot structure made of 3,000 antlers at the town’s entrance.

• Best stops: Mesa Falls (day-use fee $5), Palisades Reservoir overlook (free), and the elk antler arch in Afton (free).
• Hidden off-route spots: Bear Creek Scenic Byway (off US-89) leads to waterfalls and historic homesteads; take a short detour to Caribou Mountain for panoramic views.

The route uses well-maintained highways: US-20 east from Sun Valley, then US-26 northeast to Idaho Falls, and finally US-89 south into Wyoming. Fuel stations are plentiful in Sun Valley, Idaho Falls, and smaller towns like Swan Valley. However, the stretch between Swan Valley and Afton (about 40 miles) has limited services. Gas prices tend to be 10-15% higher near tourist areas like Jackson. No tolls are encountered, but road conditions vary—winter requires snow tires and 4WD. The speed limit is 65 mph on US-20 and 55 mph on US-89.

• Distance: 150 miles total
• Driving time: 3.5 hours non-stop
• Recommended stops: Idaho Falls, Swan Valley, Palisades Reservoir