Sea, northern Europe.
An arm of the Atlantic Ocean, connecting with the North Sea, it is 1,056 mi (1,699 km) long, covers an area of 163,050 sq mi (422,300 sq km), and has a maximum depth of 1,539 ft (469 m). It receives the Vistula and Oder rivers and many other rivers. It is enclosed by Denmark, Sweden, Finland, Estonia, Latvia, Lithuania, Poland, and Germany. It has two large arms, the Gulf of Bothnia and the Gulf of Finland . The modifying effect of the North Atlantic Current is scarcely felt; its waters contain only about one-fourth as much salt as the oceans, and it freezes readily.