Saxe-Hildburghausen (Sachsen-Hildburghausen) was an Ernestine duchy in what is now southern Thuringia, Germany. Its territory was similar to that of the modern Hildburghausen district.
In 1810, a princess of Saxe-Hildburghausen, Therese, was married to Crown Prince Ludwig of Bavaria, who became king of Bavaria 15 years later; this event is the reason for the Oktoberfest, held annually in Munich.
In 1826, the states of Thuringia were reorganised: the last ruler of Saxe-Altenburg died without an heir; the duke of Saxe-Hildburghausen became his successor, but he had to cede his own realm to Saxe-Meiningen.
In 1868, four districts were established in the Duchy of Saxe-Meiningen. Hildburghausen was one of these districts, with boundaries very similar to those of the former duchy. It remained almost unchanged until 1993, when the former district of Suhl was dissolved and most of its municipalities joined the district.
Incorporated into Saxe-Meiningen