Šešupė

The Šešupė is a 298-kilometer-long river that runs through Poland (27 kilometers), Lithuania (158 kilometers), and Russia (62 km). The river flows for 51 kilometers along the boundary between Russia's Kaliningrad Oblast and Lithuania. The Šešupė begins at the Polish village of Szeszupka, about ten miles from the Polish-Lithuanian border, and flows into the Nemunas near the town of Neman, on the boundary between Lithuania and Kaliningrad Oblast. Kudirkos Naumiestis, Pilvikiai, Marijampol, and Kalvarija are major towns and cities along the river from the Nemunas to the source. On the other side of the river, there are sections of Kaliningrad and Lithuania, including a tiny island that is largely Russian but includes a Lithuanian portion.

The name Šešupė's etymology is unclear. In Lithuanian, up means river. There is an association with the word šeši, which means number six in Lithuania, and the river name could be interpreted as "river of six" or simply "six rivers," but the most likely etymology is that part of the name "e" is derived from the term šėšėlis, which means shadow, and the river name itself could be translated as a "shadow river."

Length: 298 km