Geography of the Baltic, the Kattegat and the Skagerrak

The sea surrounding Sweden is a part of the Northern Atlantic. It lies on the North West European continental shelf and is relatively small and shallow. Basic information such as drainage areas, the shape of the sea, area, depth, volume and contact points with neighbouring seas is needed to understand the principle oceanographic processes.

The sea areas around Sweden include the coast and the archipelago areas. The limit for the Baltic is the narrowest, shallowest part of the Sound and the Belt.

There are more ways to divide the sea. Navigational charges that reflect the situation on the surface use a different division. Below is the oceanographic division that is used by Swedish authorities that work with sea water.

The Baltic

The Baltic is divided into the Baltic Proper and the Gulf of Bothnia. The boundary goes through the Archipelago Sea and the Åland Sea.

The Baltic Proper can be further subdivided into the Belt Sea, the Sound, the Arkona Sea, the Bornholm Sea, the East Gotland Basin, the Northern Gotland Sea, the West Gotland Sea, the Gulf of Riga and the Gulf of Finland.

The Gulf of Bothnia is split into the Bothnian Sea and the Bothnian Bay.

Coastal areas

The coastal areas are split up into a total of 587 coastal waters and archipelago areas.

Area, depth and volume

For each sea area, the area, depth distribution and cross sectional contact with neighbouring areas have been calculated.


Baltic: 386 700 km²
Skagerrak and Kattegat: 61 000 km².


The Skagerrak is deepest at 700 m. It is followed by the western Gotland Sea where the depth at Landsort is 459 m. The Åland Sea has a depth of 301 m and the Bothnian Sea is 293 m deep.


The volume of the Baltic is 20 800 km³ and the total for the Skagerrak and the Kattegat is 6 700 km³.

Drainage areas

Drainage areas are the areas of land that drain into a lake or the sea. The rain that falls over a drainage area and which does not evaporate flows over and through the ground, into lakes and rivers and ends up in the sea.

Drainage into the Baltic

The total drainage area into the Baltic is 1 665 000 km². 14 countries have all or part of their land in the Baltic drainage area, and 56 million people live in this area.

The five largest lakes are Ladoga (17 800 km²), Onega (9 900 km²), Vänern (5 650 km²), Peipsi (3 560 km²) and Vättern (1 900 km²).

The five rivers with the largest watershed are the Neva (284 000 km2), Vistula (193 000 km²), Odra (122 000 km²), Neman (98 100 km²) and Daugava (84 000 km²).

Drainage into the Kattegat and the Skagerrak

The drainage area is 199 600 km². The largest lake is Vänern (5650 km²) and the rivers with the largest watersheds are Göta Älv (50222 km²) and Glomma (43030 km²).