Starhemberg Castle, also known as Eferding Castle, is a historic building in the center of the city of Eferding that has been owned by the princely Starhemberg family for around 450 years. The castle was originally built in the 12th century by the diocese of Passau as an official residence and sold to the Counts of Schaunberg in the 14th century. The Schaunbergers had today's north wing built, which dates back to the Middle Ages. After the Schaunbergers died out in the 16th century, the castle came to the Starhembergers, who converted it into a representative castle in the classicist style. The current owner of the castle is the ninth Prince of Starhemberg, Georg Adam.
Starhemberg Castle is not only a private family home, but also a cultural center and a meeting place. The castle has a private library and three museums that deal with the history of Eferding and the castle owners. The castle is also a member of the Austrian association Via Imperalis, which is responsible for the promotion and preservation of European cultural assets. The castle is also the venue for various public events, such as the annual castle Advent, which is a meeting point for friends of the original customs and traditions.