Aerial view of Bosanska Otoka. Bosanska Otoka is a town on the river Una in Bosnia and Herzegovina. The town was once known as Otok, the local word for island. It lies on the ancient Roman road connecting the Podunavlje region to the Adriatic Sea. Otoka spans both banks of the River Una and includes 24 river islets. The right and left banks are connected by a steel bridge built in 1920.