Lithuania, Country of north eastern Europe, the southernmost and largest of the three Baltic states. Lithuania is bounded by Latvia to the north, Belarus to the east and south, Poland and the detached Russian oblast of Kaliningrad to the southwest, and the Baltic Sea to the west. The official language of Lithuania is Lithuanian. Russian, Polish, Belarusian, Ukrainian, and other languages are spoken in the larger cities. Yiddish is commonly spoken by members of the tiny remaining Jewish community in Lithuania. Lithuania was the last pagan country in Europe, accepting Roman Catholicism in the late 14th century.