Appalachian Trail, officially Appalachian National Scenic Trail, hiking path, 2,144 mi (3,450 km) long, passing through 14 states, E United States. Conceived in 1921 by Benton MacKaye, forester and regional planner, and completed in 1937, the trail extends along the ridges of the Appalachian Mts. from Mt. Katahdin, Maine, to Springer Mt., Ga. The largest part of the trail passes through eight national forests and two national parks, but some of its length is still on private property. Hiking and trail clubs maintain shelters and campsites along the path. The Appalachian and Pacific Crest scenic trails, both designated in 1968, were the first two components in the National Trails System. In 1999 the International Appalachian Trail, a 690-mi (1,110-km) extension of the trail north and east from Mt. Katahdin into New Brunswick and Quebec to Cape Gaspé, was dedicated. Sections of this trail pass through Canadian national and provincial parks.