Laramie to Island Park Road Trip: Complete Guide

This 430-mile route from Laramie (elevation 7,165 ft) to Island Park (elevation 6,300 ft) traverses southern Wyoming's high desert, crosses the Continental Divide at 7,200 ft, then descends into Idaho's volcanic plateau along the Henrys Fork of the Snake River. The drive takes approximately 6.5 hours without stops, but the landscapes demand exploration.

Geologically, the route follows the edge of the North American Plate, passing through the Laramie Basin (a former inland sea) and the Snake River Plain (shaped by the Yellowstone hotspot). Historically, it mirrors the Oregon Trail corridor, with wagon ruts still visible near Guernsey.

For drivers, note a quirk: Wyoming's I-80 has a 75 mph speed limit, but strong crosswinds often reduce safe speeds to 60 mph, especially near Elk Mountain. Idaho's US-20 is mostly 70 mph but has occasional abrupt slowdowns for small towns.

The route offers stark beauty: the Medicine Bow National Forest near Laramie gives way to the Red Desert's badlands, then the Green River Basin's sagebrush. Near Kemmerer, fossil sites (Fossil Butte National Monument) preserve 50-million-year-old fish. In Idaho, the Caribou-Targhee National Forest features lava flows and the Big Springs trout hatchery.

• Continental Divide: Crossed at 7,200 ft near Rawlins. A sign marks the spot.
• Fossil Butte NM: UNESCO-designated fossil site; 45-minute detour near Kemmerer.
• Big Springs ID: One of the largest freshwater springs in the U.S., forming the Henrys Fork.

Local commerce: Rock Springs has a coal mining heritage; stop at the Rock Springs Historical Museum. Kemmerer is home to the J.C. Penney mother store. Soda Springs offers geyser viewing (captive geyser erupts hourly). Idaho Falls has a riverfront greenbelt and the Idaho Falls Temple.

For unique shopping, visit the Fossil Country Museum in Kemmerer or the Idaho Falls Farmers Market (summer Saturdays).

Safety: Watch for wildlife (antelope, deer) at dawn and dusk, especially between Rawlins and Rock Springs. I-80 has truck traffic; use rest areas to avoid fatigue. Snow possible October-April; check road conditions via WYDOT.

• Family stops: Fossil Butte NM (junior ranger program), Big Springs (boardwalk and fish feeding), Island Park (Mesa Falls Scenic Byway).
• Pet-friendly: Leashed dogs allowed at Fossil Butte and Big Springs; rest areas have pet walks.

Fatigue management: Plan stops every 2 hours. Recommended rest zones: Little America rest area (milepost 136), Fort Bridger (milepost 35), and Soda Springs Geyser Park.

Hidden off-route spots: The Killpecker Sand Dunes (north of Rock Springs) offer 14,000-acre dune field; access via unmarked dirt road. The Lava Hot Springs in Idaho (detour via US-30) have natural thermal pools.

For more on discovering off-the-beaten-path stops, see our guide: how to find the best stops and hidden gems between cities.

The primary route is I-80 west from Laramie to Rawlins, then US-287/US-30 to Rock Springs, continuing on I-80 to Evanston, then US-189 north to Kemmerer, and US-30 west to Soda Springs, finally US-20 northwest to Island Park. An alternative is to take I-80 to Lyman, then WY-414 to US-30, bypassing Evanston.

• Fuel: Stations every 50-70 miles on I-80; fewer on US-20. Fill up in Rawlins, Rock Springs, and Idaho Falls.
• Food: Limited options between Rock Springs and Kemmerer; pack snacks.
• Restrooms: Rest areas at Elk Mountain, Wamsutter, and Little America.
• Cell coverage: Spotty in Wyoming high desert (AT&T better than Verizon); good in Idaho Falls onward.