The Castle of the Masovian Dukes is a Gothic castle located in Czersk (36 km south of Warsaw), Masovian Voivodeship in Poland. The castle was built on the turning point of the fourteenth and fifteenth century.

The Masovian dukes castle in Czersk was built on the turning point of the fourteenth and fifteenth century, by Duke Janusz I. When the Masovian land became part of the Kingdom of Poland - which was under the rule of Queen Bona Sforza. Primarily, the castle had three towers, one of them - being four-sided, was used as the main gate house.

During the war with the Swedes, in 1656, the castle became partly ruined. The retreating land army, close to Warta, under Stefan Czarniecki's commandhad captured the stronghold and had devastated it. The castle went through a reconstruction between 1762–1766, when Marszałek Franciszek Bieliński had commanded the reconstruction of the stronghold. However, due to the Prussian Partition, the Prussian leader had ordered for the demolition of the castle's defense walls, reducing the stronghold's military importance. From that time, nobody had every again took on the reconstruction of the castle. From the once mighty stronghold, all of the towers; a brick bridge from the eighteenth century; and the north and east wing of the castle had all survived.