RIOUW, Rhiouw or Bintang, an archipelago of the Dutch East Indies, E. of Sumatra, and separated from the Malay Peninsula by the Straits of Singapore. With the Lingga, Karimon, Tambelan, Anambas and Natuna Islands, to the N.E., E. and S., and the territory of Indragiri in Sumatra, it forms the Dutch residency of, Riouw and dependencies. The seat of government is at Tanjong Pinang, a small port of 4000 inhabitants (including 160 Europeans and about 2000 Chinese), on the S.W. coast of the chief island, Bintang or Riouw. The total area of the residency is about 17,550 sq. m., and its population (1905) 112,216, of whom considerably over a quarter are Chinese. These cultivate gambier and pepper successfully in Bintang, and there is a considerable trade in wood. Bintang has an area of about 440 sq m., and is surrounded by many rocks and small islands, making navigation dangerous. The soil is not fertile, and much of it is swampy. There is an assistant residency of Lingga, to which belongs the island of Singkep, where extensive tin-deposits are worked. Geologically the Riouw and Lingga Islands are appendages of the Malay Peninsula, not of Sumatra. Bintang is mentioned by Marco Polo under the name of Pentam, which is not far from the genuine Malay name Bentdn, said to mean a half-moon. After the Portuguese conquest of Malacca (1511), the expelled Mahommedan dynasty took up its residence on Bintang, where it long fostered piracy.