The Narew ([ˈnarɛf]; Belarusian: Нараў, romanized: Naraŭ; Lithuanian: Narevas or Naruva) is a 499-kilometre (310 mi) river primarily in north-eastern Poland.
[2] The portion of the river between the junctions with the Western Bug and the Vistula is also known as the Bugonarew, Narwio-Bug, Narwo-Bug, Bugo-Narew, Narwiobug or Narwobug.
At the confluence near Zegrze the Bug is 1.6x longer, drains a 1.4x larger basin, and has a slightly greater average discharge (158 m³/s at Wyszków vs 146 m³/s at Pułtusk for the Narew, both ~25 km above the junction).
On December 27, 1962, Prime Minister Józef Cyrankiewicz abolished the name Bugonarew soon after the Zegrze Reservoir had been constructed.
On August 23, 1939, the Soviet Union and Germany signed the Molotov–Ribbentrop Pact, agreeing to divide Poland along the Narew, Vistula (Wisła), and San rivers.