APURIMAC, a river of central Peru, rising in the Laguna de Villafra in the western Cordilleras, 7 m. from Caylloma, a village in the department of Arequipa, and less than 100 m. from the Pacific coast. It flows first north-easterly, then north-westerly past Cuzco to the mouth of the Perené tributary, thence east and north to its junction with the Ucayali at 10° 41′ S. lat., and 73° 34′ W. long. It is known as the Apurimac only down to the mouth of the Mantaro tributary, 11° 45′ S. lat. and 1325 ft. above sea-level. Thence to the mouth of the Perené (984 ft.) it is known as the Ené, and from that point to its junction with the Ucayali (859 ft.) as the Tambo.