Waroux Castle, Medieval château in Alleur, Belgium

Waroux Castle is a circular fortress in the municipality of Ans with walls of flint and limestone on the exterior and brick construction inside. The building functioned as both a residence and a defensive stronghold, anchored by two prominent towers.

The name Waroux recalls the war between the Awans and Waroux families that divided Hesbaye's nobility from 1298 to 1335. The de Waroux family held the seigneurie, dependent on the county of Looz in the 13th century, until it passed by marriage in 1525 to Richard de Merode. Bricks dated 1696 bearing the Clercx arms suggest the Merode sisters sold it to Michel Clercx; the Clercx de Waroux family kept it until 1925, and the commune of Ans bought it in 2005.

The name recalls the War of the Awans and Waroux (1298–1335), a feud among Hesbaye nobles that also destroyed a windmill said to date from 1323. The castle now houses offices and meeting rooms, and has hosted art exhibitions, including a 2007 Rodin show and a 2006 Folon exhibition. In September 2007 its park held a Napoleonic bivouac with infantry, artillery and cavalry.

The castle stands on rue de Waroux in Alleur, part of the municipality of Ans in Liège Province. It now houses offices and meeting rooms, so the interior is not a museum open to walk-in visitors; the building and its lawn are best seen from the street. The castle and its adjoining farm were listed as protected heritage on 25 October 1977.

The round shape of this fortress is uncommon in Belgium and reflects an unusual medieval building strategy. The circular design offered defensive advantages by providing equal protection from all directions.