The
Gulf of Finland (; ; ; ) is the easternmost arm of the
Baltic Sea. It extends between
Finland (to the north) and
Estonia (to the south) all the way to
Saint Petersburg in
Russia, where the river
Neva drains into it. Other major cities around the gulf include
Helsinki and
Tallinn. The eastern parts of the Gulf of Finland belong to Russia, and some of Russia's most important oil harbours are located farthest in, near Saint Petersburg (including
Primorsk). As the seaway to Saint Petersburg, the Gulf of Finland has been and continues to be of considerable strategic importance to Russia. Some of the environmental problems affecting the Baltic Sea are at their most pronounced in the shallow gulf.