The castle in Bobrowniki was probably built around the middle of the 14th century. Its founder was the duke of Dobrzyń Land, Władysław the Hunchback. During the wars of the second half of the 14th – early 15th century, the castle passed from time to time from the Teutonic Knights to Polish and from Polish to the Teutonic Knights. Eventually, after 1411, it returned to Poland and on the initiative of king Władysław Jagiełło was considerably expanded. When the Second Peace of Toruń in 1466 ended Polish-Teutonic war, the castle lost its military significance and became the seat of the staroste. In the seventeenth century it was ravaged by the Swedes, although, as the graphics from 1627 show, it was previously partly ruined. Eventually, it was pulled down in the 19th century.
The castle was located on an island surrounded by the Vistula waters. The earliest complex was a square of about 46,5 meters. It consisted of a main house based on a western curtain, a cylindrical tower with a four-sided base and a low gate tower. In the fifteenth century, the perimeter of the outer walls was added, the gate was extended by foregate, and towers were built at the corners. Later remodeling was associated with the creation of additional houses reducing the area of the inner courtyard.
Currently, only the elements of the defensive walls, mainly the northern and southern part, as well as the relics of the tower are a trace of the former splendor of the building. Picturesque ruin is open to visitors.
Leksykon zamków w Polsce, L.Kajzer, S.Kołodziejski, J.Salm, Warszawa 2003.