Slovenia (in Slovenian, Slovenija), republic in south-eastern Europe, on the Balkan Peninsula, bordered on the north by Austria, on the north-east by Hungary, on the south-east and south by Croatia, and on the west by Italy and the Adriatic Sea. Formerly a constituent republic of the Socialist Federal Republic of Yugoslavia, Slovenia proclaimed its freedom in June 1991. It joined the UN in May 1992. The republic has an area of 20,254 sq km (7,820 sq mi). Ljubljana is the capital and largest city.