Klagenfurt am Wörthersee, or simply Klagenfurt, is the capital of the federal state of Carinthia in Austria. With a population of 99,100, it is the sixth-largest city in the country. The city is the bishop's seat of the Roman Catholic Diocese of Gurk-Klagenfurt and home to the Alpen-Adria-Universität Klagenfurt. It is on the lake Wörthersee and on the Glan River. The city is surrounded by several forest-covered hills and mountains with heights of up to 1,000 m (3,300 ft), for example, Ulrichsberg. To the south is the Karawanken mountain range, which separates Carinthia from Slovenia and Italy.