major tributary of the Orinoco in eastern Colombia and western Venezuela. Formed in Meta department, Colombia, by the junction of the Upía and Guayuriba rivers, which descend from the eastern slopes of the Cordillera Oriental of the Andes, the Meta meanders east-northeastward across the Llanos (plains) of northern South America. At Nueva Antioquia, Colom., the river turns generally eastward, forming the border between Colombia and Venezuela. It empties into the Orinoco between Puerto Carreño, Colom., and Puerto Páez, Venezuela. Much of its 650-mi (1,046-km) length is navigable, but it is not a major transportation artery since the area it drains is sparsely populated.