The body of water that separates Sweden and Finland is the Baltic Sea, the northern part of which is the Gulf of Bothnia located between the west coast of Finland and the east coast of Sweden. It is 725 kilometers long, approximately 80 to 240 kilometers in width, has an average depth of 200 ft, and it has a surface area of approximately 117,000 square kilometers.
The salinity of the Gulf of Bothnia is extremely low because it receives its water from so many rivers such as Kemijoki, Skellefte, Pite, Kokemaenjoki, Oulujoki, Dalalven, Angerman, Torne, Ume and Lule. With an extremely low salinity, the Gulf of Bothnia gets covered with ice for more or less than five months during winter.
