Sejny (Lithuanian: Seinai) is a town in north-eastern Poland, in Podlaskie Voivodeship, close to the border with Lithuania and Belarus. It is located in the eastern part of the Suwałki Lake Area (Polish: Pojezierze Suwalskie), on the Marycha ("Seina" in Lithuanian from which the town bears its name) river, being a tributary of Czarna Hańcza. As of 1999 it had almost 6,500 permanent inhabitants, with many more inhabiting the area in the tourist season, and was the capital of a separate powiat.