The Main Street Historic District encompasses the historic commercial center of Damariscotta, Maine. Although the community was settled in the 18th century, most of its downtown area dates to the second half of the 19th century due to an 1845 fire. Lining Main Street east of the Damariscotta River, the downtown has a well-preserved collection of commercial, residential, and civic structures from the period. The district was added to the National Register of Historic Places in 1979, and enlarged in 2001.