Heistard Castle, Castle in North Rhine-Westphalia, Germany

Heistard Castle, also called Wasserburg Holzheim, is a water castle in Mechernich with a rectangular shape surrounded by a wide moat. Today, parts of the original structure remain standing, including the ring wall and a striking round tower made of rough stone, about 14 meters high with four floors.

Heistard Castle was first documented in 1333, but the surviving structures were likely built from 1486 onward. The manor house was rebuilt in the 15th and 16th centuries, the gate tower, demolished in 1846, dated from the 17th century, and the farm buildings were expanded in the 17th and 18th centuries. Work on the east wing continued into the 19th century.

The castle is privately owned and run as a farm, so the grounds are working agricultural land rather than a museum. Its alternative names, Holzheim and Heistartburg, tie it to the village of Holzheim in Mechernich. The 14-metre round tower of quarry stone in the north corner is the element most often pointed out to visitors passing by.

The castle is in private hands and used as a farm, so visitors can only see the exterior from nearby roads. The interior is not open to the public, so plan to view the outer structure and surrounding landscape from a distance.

The surviving round tower is built of quarry stone, stands 14 metres high and has four storeys; it rises at the north corner of the rectangular moat-ringed complex. The outer walls still carry arrow slits, and a rampart runs along the west and south sides outside the moat.