Whilst castles built by the Savoys generally have a square plan with a circular tower at each corner, Chillon Castle is special in that it follows the oval form of the 100m X 50m island it is built on.
It is surrounded by a natural moat, and is accessible from the lake on all sides.
On the land side it can be entered by crossing the wooden bridge. Formerly there was a drawbridge, the remains of whose pulley system can still be seen.
Chillon is a double function castle. The façade opposite the mountain, pierced by arrow slits and loopholes and topped by machicolations on the battlements, is the fortress that protects the road, the Via Italica. Facing the lake, magnificent Gothic windows adorn the façade of the princely residence. The keep in the centre of the castle is linked to the dwelling via the sentry walks.
The three inner courtyards correspond to the use of the buildings surrounding them: the castellan’s or constable’s residence, and the lord of the castle’s apartments.