Riau is a province of Indonesia. It is located in the central eastern coast of Sumatra along the Strait of Malacca. Until 2004 the province included the offshore Riau Islands, a large group of small islands (of which the principal islands are Batam and Bintan) located east of Sumatra Island and south of Singapore, before these islands were split off as Riau Islands Province in July 2004. The provincial capital of Riau Province and its largest city is Pekanbaru.