The Baltic Soviet republics - Estonian, Latvian and Lithuanian - are located on the northwestern outskirts of the East European, or Russian, plain. The Baltic states are stretched from north to south for 730 km, from west to east - for 440 km. Latvia and Litvatselik are on the mainland. Estonia owns several hundred islands included in the West Estonian (Moonsund) archipelago. The sea border running from the mouth of the Narva River in the Gulf of Finland to the mouth of the Neman River (Nemunas) in the Kursk (Curonian) Gulf is about 1200 km and, with adjacent territorial waters, is simultaneously the state border of the Soviet Union.