The Castle of Hollogne sits in a wooded area of the Geer valley in Hollogne-sur-Geer, Liège, Wallonia. The castle features brick construction with limestone ornaments, two stories, and cylindrical towers topped with a pitched roof and dormers. Originally controlled by Cornelimunster Abbey until the 13th century, the castle was destroyed during the medieval conflict between the Awans and Waroux families. Today, the remains include a round corner tower and rectangular structures likely dating from the 17th to 19th centuries, though the grounds are fenced and not open to visitors.