river that rises as the Caquetá River east of Pasto, Colombia, in the Colombian Cordillera Central. It meanders generally east-southeastward through the tropical rain forest of southeastern Colombia. After receiving the Apaporis River at the Brazilian border, it takes the name Japurá and flows eastward to join the stretch of the Amazon known as the Solimões River, above Tefé. Its total length, including the Caquetá, is about 1,750 miles (2,820 km). At its mouth it forms a network of channels and large islands, with seasonal lakes. The river, which has a strong current, is navigable for small boats in Brazil.