a fortified town of Prussia, province of Brandenburg, at the junction of the Wartha with the Oder, which is here crossed by a bridge 875 feet in length, 16 miles N. of Frankfort. The town is surrounded by lakes and marshes, which greatly add to its strength. It contains a castle in which Frederick the Great was confined by his father. The manufactures comprised woollens, hosiery, leather, starch, brandy, and bear. Küstrin was taken by the French in 1806. Pop. (1849) 8310.