To be privately owned
Kammer Castle

In Schörfling am Attersee, Upper Austria, stands Kammer Castle, a moated castle. Originally situated on an island and now on a peninsula in the northern Attersee, the structure is a rectangular, three-story building with two low side wings enclosing an inner courtyard.
History+
The first mention of Kammer Castle dates back to 1165 with Haidfalk von Chammer as its owner. From the 13th century, a stronghold developed here, becoming the center of the Attergau as a fief of the County of Schaunberg. In 1386, following a feud between Count Heinrich von Schaunberg and Duke Albrecht III of Austria, the castle was forcibly sold to the Habsburgs. Under Habsburg rule, Kammer was pledged multiple times before being sold in 1581 by Emperor Rudolf II to Baron Johann Khevenhüller. The Khevenhüller family retained the castle even after selling other properties.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Schloss-Kammer-von-Seewalchen.jpg
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: 47.9461, 13.5914