The four-tower moated castle was built by the Lengenbachers, one of the most powerful noble families in the Babenberg era, and was first mentioned in 1201. Structurally, it shows similarities with the oldest part of the Vienna Hofburg, the Swiss Wing.
In the 15th century, Orth Castle was the scene of disputes between Emperor Friedrich III. and the Lower Austrian Estates, who regarded Ladislaus Postumus as their rightful sovereign. On August 15, 1452, the castle was taken by an army of estates led by Ulrich von Eyczing from the Eyczinger noble family. After the death of Ladislaus in 1457, new troubles arose. In 1460 an imperial army besieged the castle held by Gamareth Fronauer of the von Fronau noble family, which he regarded as his heir. In distress, Gamareth fled through underground passages, whereupon the castle was taken without a fight on March 26, 1460.
The castle was destroyed in 1529 during the first Turkish siege and rebuilt by Niklas Graf Salm the Elder in the Renaissance style. In the 17th century it was used for court hunts and expanded in 1679/80 in a baroque style. An extension, the so-called Neuschloss, was built directly on the west side. In 1824, the Habsburgs bought the castle from Count Moritz von Fries and incorporated it into the private and family fund. Crown Prince Rudolf used it as a hunting lodge and had it refurnished in a late historicist style around 1873.
Orth Castle was renovated in 2005 and houses the National Park Center of the Donau-Auen National Park and the museumORTH as well as the event center, both operated by the market town of Orth.
The schlossORTH National Park Center is open daily from March 21st to November 1st and offers information and booking services for guided national park tours, the DonAURooms exhibition and the Schlossinsel floodplain adventure area with animals and plants typical of the floodplain landscape.