The Lewis and Clark National Historic Trail is a route across the United States commemorating the Lewis and Clark Expedition of 1804 to 1806. It is part of the National Trails System of the United States. It extends for some 3,700 miles from Wood River, Illinois to the mouth of the Columbia River in Oregon.
The trail is administered by the National Park Service, but sites along the trail are managed by federal land management agencies, state, local, tribal, and private organizations. The trail is not a hiking trail, but provides opportunities for hiking, boating and horseback riding at many locations along the route. The trail is the second longest of the 23 National Scenic and National Historic Trails. It passes through portions of Missouri, Kansas, Iowa, Nebraska, South Dakota, North Dakota, Montana, Idaho, Oregon, and Washington.