The Gulf of Bothnia is considered part of Europe. It is the northernmost arm of the Baltic Sea, lying between Sweden and Finland in northern Europe.
The gulf is divided into the Bothnian Bay in the north, the Kvarken region in the middle, and the Bothnian Sea in the south. Its waters are unusually low in salinity because many rivers flow into it and the connection with the Atlantic is limited. Much of the gulf freezes during winter.
The surrounding region also shows dramatic post-glacial rebound. The land is still rising after being pressed down by enormous ice sheets during the last Ice Age, especially around Kvarken. Over roughly 2,000 years, this uplift may divide the northern bay from the rest of the gulf and create a large freshwater lake.
A common mix-up is treating the Gulf of Bothnia as a separate ocean or as part of Scandinavia alone. Geographically, it is a European sea area bordered principally by Sweden and Finland, and it belongs to the Baltic Sea system.