Muhu (German: Mohn/Moon; in Estonian also called Muhumaa), is an island in the Baltic Sea. With an area of 198 km2 (76 sq mi) it is the third largest island belonging to Estonia, after Saaremaa and Hiiumaa.
Together with neighbouring smaller islands of Kesselaid, Viirelaid, Võilaid and Suurlaid it forms Muhu Parish (Estonian: Muhu vald), the rural municipality within Saare County. The municipality has a population of 1,697 (as of 19 April 2010) and covers an area of 206.12 km2 (80 sq mi). The population density is 8.8/km2 (23/sq mi).
The most important villages in Muhu are Kuivastu, Liiva (where the school can be found) and Koguva. In Pädaste, an internationally renowned luxury hotel and spa operates in the restored manor house.
The island is divided from mainland Estonia by the Suur Strait (Moonsund) and from Saaremaa by the Väike Strait. It is linked by ferry to Virtsu in the mainland, and to Saaremaa by a causeway, the Väinatamm. In winter an ice road connects the island to the mainland.
In January 1227, an army of the Livonian Brothers of the Sword with Letts, Germans of Riga and native Livonians (20,000 men commanded by William of Modena) crossed on sea ice from the mainland and attacked the island of Saaremaa to reduce the last holdout of pagan Estonians. The Estonians surrendered on Muhu at a circular stronghold called Mona, the earthworks of which are still preserved near the causeway between the islands. This ended the Estonian Crusade.