Coanza, a river of S. W. Africa, flowing into the Atlantic ocean on the coast of Lower Guinea, south of St. Paul deLoanda, in lat, 9° 20' S. and lon. 13° 12' E. Its source is supposed to lie eastward of Bihe, between lat. 12° and 13° S. and lon. 17° and 18° E. Its general course thence to the sea is in a northwesterly direction. The entire length of the river is estimated at not less than 500 m. The entrance to the Coanza is obstructed by a bar at its mouth, though the river is navigable for light-draught steamers, if they could gain access to its waters. At the confluence of the Lucal-la, over 100 m. inland, it is about 150 yards wide. Canoe navigation extends to Cam-bambe, 150 m. from the sea, where further ascent is prevented by a large waterfall. There is another cascade above this, at the junction of the Lombe with the Coanza, in lat. 9° 41' S. and about lon. 10° E., where Livingstone says hippopotami and elephants are frequently swept over and killed. Here the current is rapid and flows over a bed of sandstone rock, with pebbles. A fresh-water fish called cocasu is caught in the river, and is highly relished by the natives, who eagerly purchase it from the fishermen. Shell fish also occur.

In the lower part of its course the Coanza forms the boundary between Angola and the other Portuguese dominions on the west coast of Africa. The rich, level, and productive Portuguese settlements of Cambambe, Massangano, Muxima, and Pungo-Andongo border upon its banks. Magnetic iron ore is still worked near Massangano, where are the ruins of a massive foundery erected by the marquis of Pombal in 1758. A canal to connect the Coanza with St. Paul de Loanda was commenced by the colonial government early in the present century, but remains unfinished.