Leitha in the context of Transleithania

The Lands of the Crown of Saint Stephen (Hungarian: a Szent Korona Országai, lit. 'Countries of the Holy Crown'), informally Transleithania (meaning the lands or region "beyond" the Leitha River), were the Hungarian territories of Austria-Hungary, throughout the latter's entire existence (30 March 1867 – 16 November 1918), and which disintegrated following its dissolution. The name referenced the historic coronation crown of Hungary, known as the Crown of Saint Stephen of Hungary, which had a symbolic importance to the Kingdom of Hungary.

According to the First Article of the Croatian–Hungarian Settlement of 1868, this territory, also called Arch-Kingdom of Hungary (Archiregnum Hungaricum, pursuant to Medieval Latin terminology), was officially defined as "a state union of the Kingdom of Hungary and the Triune Kingdom of Croatia, Slavonia and Dalmatia". Though Dalmatia actually lay outside the Lands of the Crown of Saint Stephen, being part of Cisleithania, the Austrian half of the empire, it was nevertheless included in its name, due to a long political campaign seeking recognition of the Triune Kingdom, which consisted of a united Croatia, Slavonia and Dalmatia.

Cisleithania, officially The Kingdoms and Lands Represented in the Imperial Council (German: Die im Reichsrat vertretenen Königreiche und Länder), was the northern and western part of Austria-Hungary, the Dual Monarchy created in the Compromise of 1867—as distinguished from Transleithania (i.e., the Hungarian Lands of the Crown of Saint Stephen east of ["beyond"] the Leitha River). This name for the region was a common, but unofficial one.