Etang Castle, locally known as Château de l'Etang, lies north east of the village of Audigny in the Aisne department in the Picardy region in France.
When exactly Etang Castle was built is not known. Looking at the present remains I would say it dates back to somwehere around the 13th century. It has a polygonal, more or less circular, plan. It used to be surrounded by a moat and was equipped with a drawbridge leading up to a gate between two round towers. Because of its position on a hill in the Oise valley, leading up to Guise, it probably served as an outpost for Guise Castle.
During its history it was extensively rebuilt and changed, especially during the 16th and 17th century. In 1655 Etang Castle was occupied by Spanish cavalry troops, led by Louis de Bourbon, the Grand Condé.
After the French Revolution the castle was transformed into a farm. During the 19th century a residential building with a small tower was built on the southern walls.
At present Etang Castle is private property and can not be visited. It can however be seen from the public road between Audigny and Beaurain. A very elegant blend between medieval remains and a more modern building, in my opinion. The castles of Guise and Wiège-Faty are nearby.