Schloss Hornegg, Medieval castle in Preding, Austria.

Schloss Hornegg is a three-storey four-wing building with an inner courtyard flanked by arcades on two sides. Its core dates from the 16th century, and the main portal bears the year 1557. Daniel von Lapp gave it its present appearance in 1875, adding a balcony on the south facade and a staircase in the north tower.

A Konrad von Horneck is documented in 1230, witnessing a settlement between the Augustinian monastery of Stainz and the lordship of Wildon; the name likely derives from Middle High German hore, marsh. The Saurau family acquired the estate in 1373 and held it until 1603, when confessional disputes forced its sale; under them fish farming grew and the castle took its Renaissance form, the main portal dated 1557. From 1620 to the monastery's dissolution in 1785 it belonged to Stainz Abbey.

The radio presenter Carl Graf Schönfeldt, who hosted the Vienna Opera Ball in 1963, spent his early years at Hornegg, which his father Rudolf acquired in 1917; he took the pseudonym Rudolf Hornegg after the estate. Since 1940 the property has belonged to the South Tyrolean industrial family Brigl, and the Holler family, their descendants, now runs it as an organic fish farm and holiday residence.

Gut Hornegg is a working organic fish farm with around 30 ponds, most dug in the 1960s on the site of a Baroque pond system; four historic ponds are documented by name, among them the Großer Spiegelteich and the Tobisteich. The fish are sold mainly at weekly markets in Graz, Deutschlandsberg, Leibnitz and Preding, and directly from the farm. Apartments and holiday flats are rented on the estate.

The north facade was redesigned in summer 2018 by Styrian artist Bernhard Wolf. The castle's first pictorial record is a 1681 engraving by Georg Matthäus Vischer in his Topographia Ducatus Stiriae; the first full building description dates from 1818.