The Gulf of Bothnia is located between Sweden and Finland. It is part of the Baltic Sea, a Mediterranean body of water that is composed of both fresh and salt water.
The Gulf of Bothnia is the northern part of the Baltic Sea and is made up of 80 percent fresh water and 20 percent salt water. It is prone to ice coverage in winter months. The northernmost part of the Gulf of Bothnia is Bothnia Bay, while the southern area is the Bothnian Sea.
Other parts of the Baltic Sea include the Gulf of Riga in the east, Gulf of Finland in the northeast, the Northern Baltic Sea, the Bays of Gdansk and Pomerania in the south, the Bay of Kiel in the west and the Baltic Proper.