Hillenraad Castle

Hillenraad Castle is a historic fourteenth-century square water castle situated on the southern edge of Swalmen, within the municipality of Roermond in the Dutch province of Limburg. Nestled in the middle of an estate near the village of Boukoul, the complex features a moated main building distinguished by four corner towers, an outer castle, various outbuildings, and an expansive castle park. Although the exact construction date is not recorded, historical deeds suggest the structure was erected after 1339, with the first definitive mention of the house occurring in 1380 under the ownership of Didderic van Oest. The site originally evolved from lands pledged by the Van Swalmen family, eventually becoming a unified fiefdom that included the adjacent Hoppenrade fields.

The castle holds significant historical value due to its strategic role and long lineage of noble ownership. In 1382, owner Dirk van Oest signed a treaty with the city of Cologne, pledging the castle for military use against the local archbishop, though peace was restored before the fortress was ever utilized for battle. Through the marriage of Isabella van Oest in 1486, the property passed to the influential Schenck van Nydeggen family. Architecturally, the castle has transformed from what was likely a simple rectangular house with a single round tower in the fourteenth century to the more elaborate fortified structure seen today.

Recognized for its cultural heritage, Hillenraad Castle was designated a protected national monument in 1970. The registration covers twenty separate entries, encompassing the main edifice, auxiliary buildings, and specific landscape elements within the park. Despite its historical importance and well-preserved condition, the castle remains private property and is not open to the public. It stands as a prominent example of Limburg's medieval architectural history, maintaining its moated defenses and estate grounds while remaining closed to general tourism.