The Šešupė ; Russian: Шешупе; German: Scheschup(p)e; Polish: Szeszupa) is a 298 km long river that flows through Poland, Lithuania, and Russia. The river flows for 51 km along the border between the Kaliningrad Oblast, an exclave of Russia, and Lithuania. The Šešupė originates near the Polish town of Szeszupka, about 16 km from the Polish-Lithuania…The Šešupė ; Russian: Шешупе; German: Scheschup(p)e; Polish: Szeszupa) is a 298 km long river that flows through Poland, Lithuania, and Russia. The river flows for 51 km along the border between the Kaliningrad Oblast, an exclave of Russia, and Lithuania. The Šešupė originates near the Polish town of Szeszupka, about 16 km from the Polish-Lithuanian border, and flows into the Nemunas near the town of Neman on the border between Lithuania and Kaliningrad Oblast.