The Lewis and Clark National Historic Trail is approximately 3,700 miles long, extending from Wood River, Illinois, to the mouth of the Columbia River, near present day Astoria, Oregon, following the historic outbound and inbound routes of the Lewis and Clark Expedition. The trail connects 11 states (Illinois, Missouri, Kansas, Nebraska, Iowa, South Dakota, North Dakota, Montana, Idaho, Washington, and Oregon) and many tribal lands. The trail was established by Congress in 1978 as part of the National Trails System as one of four original national historic trails, with the purpose of the identification and protection of the historic route and its historic remnants and artifacts for public use and enjoyment.
Visitors can follow the approximate route of Lewis and Clark and the Corps of Discovery Expedition by exploring the trail using a variety of transportation methods and interpretive means. Water trails along the Missouri and Columbia Rivers and their tributaries provide one means of paddling through history and vicariously experiencing the historic route. There are six designated water trails along the Lewis and Clark Trail, including the Missouri River Water Trail in Missouri; the Missouri National Recreational River Water Trail in Nebraska and South Dakota; the Upper Missouri Breaks Water Trail in Montana; the Jefferson River Canoe Trail in Montana; the Northwest Discovery Water Trail in Idaho, Washington, and Oregon; and the Lower Columbia Water Trail in Washington and Oregon. The Trail is bracketed by 6,157 mile system of roads designated by each of the 11 trail states called the Lewis and Clark Auto Route. Numerous recreational and historic sites have been developed along the trail.
The Lewis and Clark National Historic Trail may be utilized year-round.