a native state in the Island of Sumatra, on the coast of the Strait of Malacca, extending from the equator to about 3° N. Lat., and from the central mountains down to the sea. It is nearly square, about 160 miles each way, and is bounded by the river Kampar in the south, and the Assahan in the north. It derives its name from the river Siak, which traverses its central portion, and overflows the low flat regions which lie along the coast. The chief productions of the country are rice, cotton, various vegetables and fruits, honey, ivory, and bamboos. There are large numbers of cattle and game. There are numerous trading places along the coast, and several islands afford behind them shelter for ships. The whole coast, however, is very much infested with pirates. The state is governed by a sultan, who resides at Siak, the capital. At this place an active trade is carried on in the produce of the country with Singapore, Penang, &c.