CUSTRIN, or KUSTRIN  , a town of Germany, in the kingdom of Prussia, a fortress of the first rank, at the confluence of the Oder and Warthe, 18 m . N.E. from Frankfort-on-Oder and 51 M . N.E. of Berlin by rail . Pop . (1900) 16,473 (including the garrison) . It consists of the town proper within the strong fortifications, a suburb on the left bank of the Oder, and one on the right bank of the Warthe . There are three Evangelical churches and one Roman Catholic, and a handsome town hall . There are bridges over both rivers . Custrin has some manufactories of potato-meal, machinery, pianos, furniture, cigars, &c., and there is a considerable river trade . About 1250 a town was erected on the site of Custrin, where a fishing village originally stood . From 1535 till 1571 it was the residence of John, margrave of Brandenburg-Custrin, who died without male heirs in 1571 . Custrin was the prison of Frederick the Great when crown-prince, and the scene of the execution of his friend Hans Hermann von Katte on the 6th of November 1730 .