The Château Saint-Jean is a castle in the commune of Nogent-le-Rotrou in the Eure-et-Loir département of France.

[1] Château Saint-Jean, which overlooks the roads from Chartres to Le Mans and from Châteaudun to Bellême from the plateau on which its stands,[2] was built in several stages.

[2] A dry moat crossed by a drawbridge and the slope of the terrain to the west completed the defensive system.

[2] Without a garrison from the 17th century, the castle served as a prison during the French Revolution, before being sold to individuals.

[4] Purchased by the town in 1950 and partially restored between 2000 and 2004,[2] the castle has housed the municipal museum since 1959.