The Kufstein Fortress (German: Festung Kufstein) is the main landmark of Kufstein, a city of Tyrol in Austria. It is sometimes wrongly referred to as Geroldseck Fortress. It is on a hill commanding Kufstein proper. Kufstein Fortress is 507 metres (1,663 ft) above sea level.
The fortress is linked to the city below by the Festungsbahn, a funicular railway.
The fortress is mentioned for the first time in a document from 1205, where it is called Castrum Caofstein. At the time it was a possession of the Bavarian Duke Ludwig and the bishop of Regensburg. In 1415 it was reinforced by Louis VII, Duke of Bavaria. It was a fiercely fought over fortress between Bavaria and the Tyrol and had a pivotal role in an armed conflict in 1336 when Margrave Charles of Moravia had to abandon his pursuit of the Bavarians when the fortress blocked his route.
In 1342 Margarete "Maultasch", Duchesss of the Tyrol, received Kufstein as a wedding present from her husband Ludwig of Brandenburg, son of Emperor Ludwig of Bavaria. This was the first time that Kufstein became part of the Tyrol. When Margarete handed all of the Tyrol to the Habsburg Duke Rudolph IV in 1363 the Bavarians demanded that she return her original wedding gift and successfully invaded Kufstein.
In 1504 the city and the fortress were besieged and conquered by Emperor Maximilian I. Maximilian had the massive round tower built between 1518 and 1522, substantially adding to its defensibility. From 1703 to 1805 it was a Bavarian possession, returning to Austria in 1814.