display | more...
A common name (meaning "black river" in Spanish and Portuguese) given to many rivers in South America that carry dark sediment. 
The largest tributary of the Amazon River, Río Negro begins as Río Guainia in eastern Colombia. Guainia eventually reaches the border between Colombia and Venezuela, and becomes the border, flowing past the town of Maroa. At some point in the 100 km between Maroa and the junction of Brazo Casiquiare, the river changes its name. The river then flows SSE past San Felipe, Colombia and San Carlos de Río Negro, Venezuela until it reaches the town of Cucui, where it enters Brazil and descends into the rain forest.

Picking up tremendous amounts of water from the rain forest, as well as the dark sediment that gives the river its name, the river swells to a braided channel, 40 kilometers wide, with island groups so large they are referred to as archipelagoes. Some points in the river are so wide that neither shore can be seen: Water stretches to the horizon in all directions, as if one were on the high seas.

Río Negro flows east-southeast for another 1000 km or so until it meets Río Solimões (Also known as the "Upper Amazon") at the city of Manaus. The dark waters of Río Negro and the lighter waters of Solimões flow side-by-side for another 40 km until they finally mix.

A second Río Negro lies in west-central Brazil. 200 km long, it flows west through the southern portion of the swampy Pantanal region, lending its name to the southern third. The river empties into the Río Paraguay 100 km southeast of Corumba.
Just downstream from the Pantanal Río Negro, a third Río Negro collects the Rio Otuquis in Bolivia, and flows southeast for about 75 km as the border between Bolivia and Paraguay. Its confluence with Río Paraguay is the point where Brazil, Paraguay, and Bolivia meet.
A fourth Río Negro is the largest river entirely in Uruguay, flowing about 500 km WSW from Bagé just over Uruguay's northeastern border with Brazil until it meets the estuary of Río Uruguay. This river noted for its two hydroelectric dams, Rincón del Bonete, which creates the largest artifical lake in South America, and Rincón de Baygorria further downstream.
A fifth Río Negro flows for about 150 km southeast through Argentina's Gran Chaco until it mees Río Paraná at the city of Resistencia
In the region where the Pampas meet Patagonia, another Argentine Río Negro collects Río Neuquén and Río Limay near the Argentine city of Neuquén, and flows 400 km ESE into the Atlantic.
Finally, Guatemala's Río Negro is also known as Río Chixoy, site of the infamous Chixoy Dam Massacre. It winds easterly then northerly for 150 km through southwestern Guatemala until it changes its name to Río Salinas, and becomes the border between Guatemala and Mexico.
There are more, but I'm tired.
Descriptions are mine, from looking at maps in The Great Geographical Atlas, Rand McNally & Co., 1982 rev. 1989

Log in or register to write something here or to contact authors.