Carniola (Kranjska; ˈkɾàːnska, Krain; Carniola; Krajna) is a historical region that comprised parts of present-day Slovenia. Although as a whole it does not exist anymore, Slovenes living within the former borders of the region still tend to identify with its traditional parts Upper Carniola, Lower Carniola (with the sub-part of White Carniola), and to a lesser degree with Inner Carniola. In 1991, 47% of the population of Slovenia lived within the borders of the former Duchy of Carniola.
A state of the Holy Roman Empire in the Austrian Circle and a duchy in the hereditary possession of the Habsburgs, later part of the Austrian Empire and of Austria-Hungary, the region was a crown land from 1849, when it was also subdivided into Upper Carniola, Lower Carniola, and Inner Carniola, until 1918. From the second half of the 13th century, its capital was Ljubljana (Laibach). Previous overlords of Carniola had their seats in Kranj (Krainburg) and Kamnik (Stein), which are therefore sometimes referred to as its earlier capitals. Nowadays, its territory (in the extent at its dissolution) is almost entirely located in Slovenia, except for a small part in northwest Italy, around Fusine in Valromana. Carniola in its final form, established in 1815, encompassed . In 1914, before the beginning of World War I, it had a population of slightly under 530,000 inhabitants, of whom 95% were Slovenes.
The region was crossed by the Julian and Karavanken Alps. The highest mountain peaks are Nanos, ; Vremščica, ; Snežnik, ; and Triglav, . The main rivers were the Sava, Tržič Bistrica, Kokra, Kamnik Bistrica, Sora, Ljubljanica, Mirna, Krka, and Kolpa rivers. Notable lakes included Black Lake (Črno jezero), Lake Bohinj, Lake Bled, and Lake Cerknica.
Nearby is the Ljubljana Marsh, and a series of hot and mineral springs which can be found at Dolenjske Toplice, Šmarješke Toplice, and Izlake.
Agriculture thrived more in Upper Carniola than in Lower Carniola. The Vipava Valley was especially famous for its wine and vegetables, and for its mild climate.