The Orinoco is one of the longest rivers in South America at 2,140 kilometres (1,330 mi). Its drainage basin, sometimes called the Orinoquia, covers 880,000 square kilometres (340,000 sq mi), with 76.3 percent of it in Venezuela and the remainder in Colombia. The Orinoco and its tributaries are the major transportation system for eastern and interior Venezuela and the llanos of Colombia. The Orinoco is extremely diverse and hosts a wide variety of flora and fauna.

History

The mouth of the Orinoco at the Atlantic Ocean was documented by Columbus on 1 August 1498, during his third voyage. Its source at the Cerro Delgado-Chalbaud, in the Parima range, was not explored by non-indigenous peoples until 1951, 453 years later. The source, near the Venezuelan-Brazilian border, at 1,047 metres (3,435 ft) above sea level (02°19′05″N 63°21′42″W / 2.31806°N 63.36167°W / 2.31806; -63.36167 ), was explored in 1951 by a joint Venezuelan–French team.

The Orinoco delta, and tributaries in the eastern llanos such as the Apure and Meta, were explored in the 16th century by German expeditions under Ambrosius Ehinger and his successors. In 1531 Diego de Ordaz, starting at the principal outlet in the delta, the Boca de Navios, sailed up the river to the Meta. Antonio de Berrio sailed down the Casanare to the Meta, and then down the Orinoco and back to Coro.