On Dynæs in Julsø there is a 10 meter high steep castle mound. On top of it, archaeologists have found remains of rubble stones and bricks, indicating that there has been construction - probably a heavily fortified tower.
Around the castle mound, there has been a moat with water. Remains of wood have been found in the moat, which may originate from a drawbridge. On the narrow isthmus that once connected the peninsula with the mainland, there has also been a rampart. And a few hundred meters north of the castle, on a hill 70 meters above the lake surface, there has been another fortification.