Addison is a town in Washington County, named for the 18th century English author Joseph Addison, and was incorporated on February 14, 1797. Prior to incorporation it was know as Plantation Number Six west of Machias.
Located at the conjunction of the Pleasant River and the West Branch of the Pleasant River, it extends southward on a peninsular whose westerly portion comprises Cape Split in South Addison.
The town hosts two nature preserves managed by The Nature Conservancy . East Plummer Island's ten acres are densely forested and home to Bald eagles. Also managed by the State Department of Inland Fisheries and Wildlife, it is closed during early summer for nesting.
Upper Birch Island, the largest island in the Pleasant River; is home to a eagle rookery and colony of great blue herons. Seals haul out on shore ledges. Covered by mixed forest and spruce-fir stands, it is closed during nesting season.
