The Bothnian Bay or Bay of Bothnia (Swedish: Bottenviken, Finnish: Perämeri) is the most northern part of the Gulf of Bothnia, the northern part of the Baltic Sea. Its northernmost point is situated in Töre. The bay is bounded by Finland to the east, Sweden to the west, and the Kvarken sound to the south.
Major ports on Finnish side are the ports in Oulu, Kemi and Raahe.
The maximum depth of bay is 482 feet (147 m).
The bay has the highest rate of rising of land by post-glacial rebound in the Baltic Sea.