Catatumbo River, river rising in northern Colombia. It flows northeast across the Venezuelan border, crosses rich oil-bearing regions in the Maracaibo Lowland, and empties into Lake Maracaibo after a course of about 210 miles (338 km). It is navigable in its lower course and receives Zulia River 4 miles (6 km) west of Encontrados, Venez., in the Maracaibo Lowland.