The terms Baltic Sea Region, Baltic Rim countries (or simply Baltic Rim), and the Baltic Sea countries/states refer to slightly different combinations of countries in the general area surrounding the Baltic Sea in Northern Europe.
The first to name it the Baltic Sea (Latin: Mare Balticum) was 11th century German chronicler Adam of Bremen.
Depending on the context the Baltic Sea Region might stand for:
- The countries that have shorelines along the Baltic Sea: Denmark, Estonia, Latvia, Finland, Germany, Lithuania, Poland, Russia, and Sweden.
- The group of countries presently referred to by the shorthand Baltic states: Estonia, Latvia, and Lithuania.
- Estonia, Latvia, Lithuania and Kaliningrad Oblast of Russia, exclaved from the remainder of Russia.
- Historic East Prussia and the historical lands of Livonia, Courland and Estonia (Swedish Estonia and Russian Estonia).
- The former Baltic governorates of Imperial Russia: Today's Estonia and Latvia (excluding parts of modern Eastern Latvia that were part of Vitebsk Governorate).
- The countries on the historical British trade route through the Baltic Sea, i.e. including the Scandinavian Peninsula (Sweden and Norway).
- The Council of the Baltic Sea States, comprised by the countries with shorelines along the Baltic Sea, in addition to Norway, Iceland and the rest of European Union.
- The islands of the Euroregion B7 Baltic Islands Network, which includes the islands and archipelagos Åland (autonomous), Bornholm (Denmark), Gotland (Sweden), Hiiumaa (Estonia), Öland (Sweden), Rügen (Germany), and Saaremaa (Estonia).
- On historic Scandinavian and German maps, the Balticum sometimes includes only the historically or culturally German-dominated lands, or provinces, of Estonia, Livonia, Courland and Latgale (corresponding to modern Estonia and Latvia), as well as sometimes Pomerania, Kashubia and East Prussia, while the historically less-Germanized Lithuania is occasionally excluded.
- In geology, the Baltic Shield includes Fennoscandia, parts of northwestern Russia and the northern Baltic Sea.