To be privately owned
Meldegg Castle

In Singen-Beuren an der Aach stands Meldegg Castle, also known as Schlössle Meldegg. The historic structure presumably originated from a moated castle and is currently privately owned, within a garden complex.
History+
The origins of Meldegg Castle are obscure, but it is believed to have developed from a moated castle. The first written mention of the property dates back to 1568. It is presumed that the Lords of Bodman-Möggingen already resided here in the late Middle Ages. Between 1554 and 1677, the estate was in the hands of the Lords of Reichlin-Meldegg, from whom the current name is derived.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://schloesserrundschau.de/bawue/schloesser/konstanz25.html
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: 47.7978, 8.8765