Sumqayıt, city, eastern Azerbaijan. Sumqayıt lies at the mouth of the Sumqayıt River as it enters the Caspian Sea, on the northern side of the Abşeron Peninsula. Founded in 1944 as a suburb of Baku and achieving city status in 1949, Sumqayıt grew rapidly as a major chemical and metallurgical centre, largely on the basis of petroleum from the peninsula. Its vast modern factories produce aluminum, steel pipes for the oil industry, synthetic rubber, fertilizers, detergents, and petrochemicals. In February 1988 riots in the city killed more than 30 people, wounded some 200, and produced thousands of refugees; most of the victims were Armenians, who constituted a large minority of the population. Pop. (2007 est.) 268,800.