To be privately owned
Harkotten Castle

In Sassenberg-Füchtorf, North Rhine-Westphalia, Harkotten Castle is a double castle complex. It consists of two separate manor houses, which emerged from a common original castle and are still inhabited today by the descendants of the original owners.
History+
The origins of the complex date back to the 14th century, when Heinrich II von Korff built a moated castle between 1297 and 1309 to secure the borders of the Bishopric of Münster. After his death in 1334, his sons Heinrich and Eberhard divided the property, resulting in two separate manor houses. The eastern part went to Heinrich, who thenceforth called himself von Korff-Smiesing, while Eberhard received the western part. However, the outer bailey, the mill, the courthouse, the forester's lodge, the brewery, and the castle chapel remained in common ownership.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.zeche.org/
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 52.0612, 8.0325