Muhu

(also Moon), an island in the Moonsund archipelago in the Baltic Sea (part of the Estonian SSR). It is separated from the mainland by the Muhu Strait (Moonsund) and from the island of Saaremaa by the Vaike Strait. Its area is 204 sq km, including the neighboring islands. Muhu is composed of Silurian limestones and dolomites. Its surface is flat with elevations to 24 m. Muhu is connected with Saaremaa by a 4-km causeway. There is regular ferry service between Kuivastu on the eastern coast of Muhu and Virtsu on the mainland. Fishing and stock raising are the principal occupations. The village of Liiva is located on the island.

(also Muhu Väin or Moonsund), a strait between the mainland of the Estonian SSR and the islands of the Moonsund archipelago (Hiiumaa, Vormsi, and Muhu). It connects the northeastern part of the Baltic Sea and the Gulf of Riga. It is 6–27 km wide and about 83 km long. At its shallowest, the strait is 1.8 m deep. In the winter it freezes over. The ports located on the Muhu Strait include Virtsu and Haapsalu on the mainland and Heltermaa and Kuivastu on the islands of Hiiumaa and Muhu.