The four-winged palace originated from a medievalcastle and was expanded over several centuries into a Residenz. The castle originally belonged to the Lübeck prince-bishops, later it became the summer residence of the Dukes of Oldenburg. The castle was regularly occupied until the 20th century and most of the interior has survived to the present-day. Today the castle houses a museum and is open to the public in summer. It is now owned by a family foundation headed by Anton-Günther, Duke of Oldenburg. The former Baroque garden was converted during the 18th and 19th century to a landscaped park; this is the venue for the Eutin festivals.
A small, late Baroque hunting lodge on the Ukleisee belongs to Eutin Castle. The lodge was built in 1776 at some distance from the main castle at the behest of Frederick Augustus I of Saxony in order to provide a single-storey pavilion for hunting parties and guests attending special occasions.