Urubamba (ōrōbämˈbä) [key], river, c.450 mi (720 km) long, rising in the Andes Mts., S Peru, and flowing generally north to join the Apurímac River to form the Ucayali. The Urubamba is extensively used for irrigation, and its valley is heavily populated; Cuzco, Peru, is located there. High above the Urubamba's gorge are the ruins of the terraced Inca city of Machu Picchu.
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