It starts on the Delmarva Peninsula on the Atlantic Ocean and ends on the northern California coast on the Pacific Ocean. The trail has northern and southern alternates for part of its distance, passing through Chicago and St Louis respectively. The total length of the trail including both the north and south routes is 6,800 miles (10,900 km). The northern route covers 4,834 miles (7,780 km) with the southern route covering 5,057 miles (8,138 km). It is the only non-motorized coast-to-coast trail.
The trail passes through 14 national parks and 16 national forests and uses sections of or connects to five National Scenic Trails, 10 National Historic Trails, and 23 National Recreation Trails. For part of its distance, it is coincident with the North Country Trail and the Buckeye Trail.
Joyce and Pete Cottrell, of Whitefield, New Hampshire, were the first to backpack the entire official route of the American Discovery Trail. They hiked the segments out of sequence over two calendar years, finishing in 2003.
The first hikers to complete the trail in one continuous walk were Marcia and Ken Powers, a wife and husband team from Pleasanton, California. Their trailwalk lasted from February 27 to October 15, 2005. They started out from Cape Henlopen State Park in Delaware and ended at Point Reyes, California. They trailed 5,058 miles (8,140 km) by foot, averaging 22 miles (35 km) a day.
The first person to backpack the entire 6,800 miles (including both Northern and Southern sections) in one continuous hike was Mike "Lion King" Daniel. He started from Cape Henlopen State Park on June 17, 2007, and ended at Point Reyes, California on November 5, 2008.
The first person cover the entire equestrian route on horseback was Matt Parker. He undertook the journey between May 2003 and November 2005.
According to wikipedia