Eynsford Castle is a ruined medieval fortification in Eynsford, Kent. Built on the site of an earlier Anglo-Saxon stone burh, the castle was constructed by William de Enysford, probably between 1085 and 1087, to protect the lands of Lanfranc, the Archbishop of Canterbury, from Odo, the Bishop of Bayeux. It comprised an inner and an outer bailey, the former protected by a stone curtain wall. In 1130 the defences were improved, and a large stone hall built in the inner bailey. The de Enysford family held the castle until their male line died out in 1261, when it was divided equally between the Heringaud and de Criol families. A royal judge, William Inge, purchased half of the castle in 1307, and arguments ensued between him and his co-owner, Nicholas de Criol, who ransacked Eynsford in 1312. The castle was never reoccupied and fell into ruins, and in the 18th century it was used to hold hunting kennels and stables. The ruins began to be restored after 1897, work intensifying after 1948 when the Ministry of Works took over the running of the castle. In the 21st century, Eynsford Castle is managed by English Heritage and is open to visitors.