The Kolyma Gulf is the largest gulf of the East Siberian Sea

East Siberian Sea

The East Siberian Sea is a marginal sea in the Arctic Ocean. It is located between the Arctic Cape to the north, the coast of Siberia to the south, the New Siberian Islands to the west and Cape Billings, close to Chukotka, and Wrangel Island to the east...

. Its western limits are the NE projection of the Kolyma Lowlands close to the Medvyezhi Islands

Medvyezhi Islands

The Medvezhyi Islands, or Bear Islands is an uninhabited group of islands at the western end of the Kolyma Gulf of the East Siberian Sea. It is located about to the north of the mouths of the Kolyma River. The coast of Siberia is about to the southwest of the largest island, which is about km...

 in the west and the Nutel'gyrgym Peninsula and Ayon Island

Ayon Island

Ayon Island is an island in the coast of Chukotka in the East Siberian Sea. The island itself consists mainly of low lying tundra, is populated mainly by Chukchi, who use the tundra as pasture for their reindeer herds.-Geography:...

 in the east, being more than 300 km wide.

The Kolyma River

Kolyma River

The Kolyma River is a river in northeastern Siberia, whose basin covers parts of the Sakha Republic, Chukotka Autonomous Okrug, and Magadan Oblast of Russia. Itrises in the mountains north of Okhotsk and Magadan, in the area of and...

 flows into the sea in the western side of the Kolyma Gulf, forming a huge river delta

River delta

A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...

 full of islands. The bay's coastline is lowland dotted with numerous lakes and swamps. The sea in this bay is frozen for over nine months every year and is often clogged with ice floes. Other rivers flowing into the Kolyma Gulf are the Rauchua

Rauchua River

The Rauchua River is a stream in Far East Siberia. It passes through the sparsely populated areas of the Siberian tundra and flows northwards into the Kolyma Gulf, East Siberian Sea, not far west from Ayon Island....

 and the Chukochya River

Chukochya River

The Chukochya River or Bolshaya Chukochya River is a river in the Sakha Republic of the Russian Federation. It crosses the tundra roughly northeastwards and flows into the Kolyma Gulf of the East Siberian Sea west of the mouths of the Kolyma River. Its mouth is located at 70.1 N, 159.7667 E...

.

Administratively the western section of the Kolyma Gulf belongs to the Sakha Republic (Yakutia), while its eastern section belongs to the Chukotka Autonomous Okrug

Chukotka Autonomous Okrug

Chukotka Autonomous Okrug , or Chukotka , is a federal subject of Russia located in the Russian Far East.Chukotka has a population of 53,824 according to the 2002 Census, and a surface area of . The principal town and the administrative center is Anadyr...

 of the Russian Federation.