Schloss Algersdorf, Renaissance castle in Graz, Austria

Schloss Algersdorf, also called Schloss Alt-Eggenberg, stands on Baiernstraße north of Schloss Eggenberg in Graz's 14th district. Its present form dates from the 15th century and serves as a residential and administrative building. The former fortifications are no longer visible.

The castle first appears in written records in 1050 when Eppo exchanged it with the Archbishop of Salzburg for other lands. It later became the administrative center of the Eggenberg domain across the surrounding area.

The name Algersdorf goes back to the 1050 form "Algeristeti", recorded when the free lord Eppo traded the estate to the Archbishop of Salzburg. From 1586 the castle belonged to Seifried von Eggenberg and served until the mid-18th century as seat of the estate administration, later tied administratively to Schloss Eggenberg. Behind the castle, at the foot of the Plabutsch, stood the inn Zur Einsiedelei until the interwar years; a path still recalls it.

Schloss Algersdorf stands on Baiernstraße in Algersdorf, in Graz's 14th district of Eggenberg, a short distance north of Schloss Eggenberg. The building is used today as a residential and administrative property, so visitors see it from the street rather than touring the interior. The former defensive structures are no longer visible.

The castle's name recalls its earliest recorded form, "Algeristeti", noted in 1050 when the free noble Eppo traded it to the Archbishop of Salzburg for estates in the Sulm valley. Behind the building, at the foot of the Plabutsch, stood the inn Zur Einsiedelei until the interwar years; a path still carries its name.