The Duchy of Carinthia (German: Herzogtum Kärnten; Slovene: Vojvodina Koroška) was a duchy located in southern Austria and parts of northern Slovenia. It was separated from the Duchy of Bavaria in 976, then the first newly created Imperial State beside the original German stem duchies.
Carinthia remained a part of the Holy Roman Empire until its dissolution in 1806, and a crownland of Austria-Hungary until 1918. By the Carinthian Plebiscite in October 1920, the main area of the duchy formed the Austrian state of Carinthia, a small southeastern part (the present-day region of Slovenian Carinthia) was included into the newly created Kingdom of Serbs, Croats and Slovenes. The southwestern Canal Valley (Val Canale) was ceded to the Kingdom of Italy by the 1919 Treaty of Saint-Germain.
Read more about Duchy Of Carinthia: Carantania and Medieval Dynasties, Habsburgs, World War I and Carinthian Plebiscite, Area and Population