Lewis and Clark forms a loop beginning and ending in Tendoy, which is located in east-central Idaho. The byway is nearly 40 miles long and follows Old Highway 28, FSR 185, Warm Springs Road, and Lewis and Clark Highway. The roads are primarily single-lane, gravel-surfaced roads suitable for passenger vehicles. In some areas, grades exceed five percent. Lewis and Clark is normally closed to vehicles November through early June but remains open for snowmobiles.
The Lewis and Clark Back Country Byway passes through stands of fir and pine trees, across mountain meadows, and rolling hills as it climbs the Bitterroot Range to the Continental Divide and Lemhi Pass. The byway offers magnificent views of the Bitterroot and Beaverhead Mountains and the Salmon and Lemhi Valleys.
President Thomas Jefferson commissioned the expedition to explore and map the vast new territory west of the Mississippi River acquired by the United States in the Louisiana Purchase of 1803. The Lewis and Clark expedition began in May of 1804 and crossed Lemhi Pass late in the summer of 1805. Here the expedition unfurled the flag of the United States for the first time west of the Rocky Mountains, laying claim to the Pacific Northwest. At the top of Lemhi Pass is a memorial to the one woman of the expedition who served as a guide and interpreter.
The byway passes the site of Fort Lemhi, built in 1855 by Mormon missionaries. The remote outpost once had over 100 inhabitants before being abandoned in 1858. The remains of the fort are on private property, obtain permission from the landowner before inspecting!
Agency Creek Campground is a small campground maintained by the BLM. There are four campsites, all with picnic tables and fire rings. Pit toilets are also provided. There is no drinking water or trash receptacles.