The Mayn River (Russian: Майн), sometimes spelled Main River, is a river in Chukotka Autonomous Okrug (Magadan Oblast) in Russia, one of the major tributaries of the Anadyr River. The length of the river is 475 kilometres (295 mi). The area of is drainage basin is 32,800 square kilometres (12,700 sq mi). It is a right tributary, flowing roughly northwards from its source in the small Mainskoe Lake, located in the northern part of the Parapol Valley, in the Koryak Mountain Range. This river passes then through sparsely populated areas of the forest-tundra subzones of Chukotka. The vegetation of the area includes mosses, lichens, dwarf shrubs, and sedge.