La Roche-Guyon (pop. ~ 450) grew around the Château de La Roche-Guyon, built in the 12th century, to control the river Seine. Abbot Suger (St. Denis) wrote about the castle, that it was "invisible on the surface, dug in a high rock". Being on the border to the Normandie the castle had some stragetic importance. The Guy de La Roche family were the lords from the 10th to the 15th century. In the 12th century, Guy de la Roche was a vassal of Philip II of France, who rewarded his loyalty by granting him the toll for boats sailing on the Seine.

Today the village, named after Guy de la Roche, is one of the "Plus beaux villages de France" ("most beautiful villages of France").