Montreuil-sur-Mer is a sub-prefecture in the Pas-de-Calais department, northern France. It was known officially as Montreuil until 31 December 2022. It is located on the Canche river, not far from Étaples. The sea, however, is now some distance away. Montreuil-sur-Mer station has rail connections to Arras and Étaples.