Château de Montaillou

Château de Montaillou is a castle ruin perched on a hilltop in the French Pyrenees with three surviving walls of the main tower and a wide stone platform. The remains reveal how a medieval frontier stronghold was organized across multiple defensive levels.

Originally built to guard the frontier between the County of Foix and neighboring regions, the fortress fell into decline after King Louis XIII ordered its demolition in 1638. This act marked the end of its strategic importance.

The castle played a central role in investigations of Cathar communities, with records from this period now housed in Vatican archives and studied by historians worldwide.

The archaeological site is open year-round without an entrance fee, though visitors should watch for unstable stones and rough ground throughout the ruins. Sturdy footwear and a willingness to climb help you explore the different levels of the fortification.

The fortification features a clever blend of dry moats carved directly into the bedrock on two sides combined with steep natural slopes on the southern face. This mix of human engineering and natural geography reveals how medieval builders worked with the landscape itself as a defense.