RIO DE ORO, a Spanish possession on the north-west coast of Africa, extending north from Cape Blanco to Cape Bojador.
North of Cape Bojador are two zones, the southern, reaching to Cape Juby, being a Spanish protectorate, and the northern, from Cape Juby to the Wad Draa being "occupied territory." The three divisions are known collectively as Spanish Sahara. The frontier on the south traverses the middle of Cape Blanco prom ontory, thence it goes east and north in an irregular and arbi trary line till it meets the southern frontier of Morocco. East and south Spanish territory is bounded by the French Sahara. The area of Rio de Oro is about 65,000 sq.m., that of the whole of Spanish Sahara about 1 oo,000 sq.m., mainly desert. The popula tion, made up of nomad Arabs or Arabized Berbers, does not exceed 1 oo,000 and four-fif the of the people live in the two northern zones. Here, in the basin of the Saqiyet el Hamra, a river (300 m. long) reaching the Atlantic midway between Capes Juby and Bojador, are fertile regions which might repay cultiva tion, including the oasis of Smara, where is a permanent native settlement and a Kasbah (stone fort). The Spanish headquarters are at Villa Cisneros, on the peninsula forming the Rio de Oro inlet. It has about 500 European inhabitants, and since 1925 has acquired some importance as an air station. The chief ad vantage Spain derives from possession of the country is its con venience to the Canary Islands fishermen.
The peninsula of Rio de Oro is 23 m. long and r 4 to 2 m. broad and it is on an average about 20 ft. above sea-level. The estuary between peninsula and mainland is 22 m. long, 5 broad, navigable over two-thirds of its extent, with good anchorage.
History.—The estuary was taken by its Portuguese discover ers in the middle of the 15th century for a river, and, obtaining there a quantity of gold dust from the natives, they named it Rio d'Ouro (Gold River), Rio de Oro being the Spanish form. The activity of the Portuguese was before long transferred to the true auriferous regions of the Gulf of Guinea.
Spain's interest in the Saharan coast dates from the 13th cen tury, but was particularly directed to that part nearest the Canary Islands. The site of the fort of Santa Cruz de Mar Pequefia, established in 1476, though not identified, was north of Cape Bojador. The protection of the Canary Islanders engaged in the fisheries south of that point occasioned, however, the presence of Spanish warships in these waters, and small trading stations were formed at Rio de Oro, Cape Blanco and elsewhere. To preserve the interests thus acquired, Spain in January 1885 took the terri tories on the coast between capes Blanco and Bojador under her protection. The extension inland of Spanish influence was opposed by France, which claimed a protectorate over the Sahara. A convention of 1900 fixed the limits of Rio de Oro proper; by subsequent agreements with France (in 1904 and 1912) the Spanish zone was extended first from Cape Bojador to Cape Juby, and secondly from Cape Juby to the Wad Draa, the inland fron tier being fixed at 8° 4o' West. The 1912 agreement settled a matter long in dispute by fixing the southern frontier of Morocco, which had claimed the Cape Juby district, at the Wad Draa. By that agreement Spain bound herself not to cede or alienate in any form her rights in her zone of influence. In 1916 a small Spanish force was stationed at Cape Juby. It was at Cape Juby that in 1878 a British trading post had been established by Donald Mackenzie ; it was eventually made over to the Sultan of Mor occo (1895). Spanish Sahara is under the control of the Captain-General of the Canaries and a sub-governor lives at Villa Cisneros. Over the interior the authority of Spain remained almost nominal.
See Spanish Sahara (192o), a British Foreign Office handbook with bibliography ; also the Rivista and the Boletin of the Madrid Royal Geog. Soc. (F. R. C.)