Narew (nä´rĕf), Rus. Narev, river, c.275 mi (440 km) long, rising in the Białowieza Forest, W Belarus, near the border with Poland. It flows generally NW through NE Poland past Łomża, the head of navigation, then SW to the Vistula River near Warsaw. The Western Bug and the Biebrza rivers are the chief tributaries. Canals connect the Narew's tributaries with the Neman and Pripyat rivers. During World Wars I and II, major battles took place along the Narew's banks.