Lewis and Clark Trail (National Park Service)Lewis and Clark National Historic Trail is approximately 4,900 miles long, extending from Pittsburgh, Pennsylvania, 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 plus the preparatory section from Pennsylvania to Wood River, Illinois. The trail connects 16 states (Pennslyvania, West Virginia, Ohio, Kentucky, Indiana, Illinois, Missouri, Kansas, Iowa, Nebraska, 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 (NTS) as one of four original national historic trails and extended by 1,200 miles in 2019.