(also Dago), an island in the Moonsund Archipelago of the Baltic Sea; part of the Estonian SSR. The island covers an area of approximately 965 sq km and rises to a maximum elevation of 54 m. It is composed chiefly of limestones and marine deposits of the Anthropogene. Soils are gravelly and sandy. Pine forests and reeds grow along the shores. Fishing, fish processing, land cultivation, and livestock raising are the main economic activities. The city of Kärdla is located on the island.