Oulu (Swedish Uleåborg), city in western Finland, on the Gulf of Bothnia. The city is the site of the University of Oulu (1958). Oulu was founded in 1375 by the Swedes as a fortress against the Russians. It was incorporated in 1610, and during the 19th century it became a prosperous commercial center despite being badly damaged by fire in 1822. Population (2000 estimate) 117,670.