Bentheim Castle (German: Burg Bentheim) is an early medieval hill castle in Bad Bentheim, Lower Saxony, Germany. The castle is first mentioned in the 11th century under the name binithem.
The castle is built on a protusion of Bentheim sandstone, which not only provided building materials for the castle itself, but was also a valued export product. This Bentheimer Höhenrücken is the last protusion of the nearby Teutoburger forest. Its elevated position in an otherwise very flat landscape, provides an excellent view and thus a strategic location to build a castle.
The earliest history of the castle, which was erected on the remains of an earlier refuge castle is largely unknown. In the registries of Werden Abbey (1050) the castle is mentioned, as Binedheim, in and contributes grain, honey and 2 solidi. A document from 1020 names Otto von Northeim as the owner of the castle. In 1116 the castle is completely destroyed in the war between Herzog Lothar von Süpplinburg, better known as Lothar III and Heinrich V. The Annalista Saxo describes how Lothar "lays siege to Binithem, a fine and strong city and burned it after it was conquered". The epithet "strong" (firmam) suggests the castle played a vital role in the cities defences, though it is assumed it was a wooden structure, and not yet a stone one.
The castle is soon rebuilt and this time in stone by Otto von Salm, brother in law of the victorious Lothar III, whose wife Gertrud von Northeim uses it as a residence. In 1050 she is mentioned as comitissa de Benetheim, which is the first documented member of the Counts of Bentheim.