ALDHA (Appalachian Long-Distance Hikers Association) is an organization of past, present, and future hikers of the Appalachian Trail. It was formed in 1981 by previous thru-hikers of the Appalachian Trail but soon became a "users groups" for backpackers and hikers of all the U.S. scenic trails and most major hiking paths abroad. The Appalachian Long Distance Hikers Association, formed in 1981, is the only organized users' group for the Appalachian Trail, meeting annually for a three-day festival but also engaged in volunteer projects such as shelter work trips and hostel repairs. Robert Sylvester leads a team of 25 volunteer field editors who contribute annual updates for the Companion.