Oulu was founded on April 8, 1605, by King Charles IX of Sweden opposite to the fort built on the island of Linnansaari. This took place after favorable peace settlements with the Russians, which removed the threat of attack via the main east-west waterway, the river Oulu. The surrounding areas were populated much earlier. Oulu is situated by the Gulf of Bothnia, at the mouth of river Oulujoki, which is an ancient trading site. One possible source for the name Oulu is a word in the Sami language meaning 'flood water', but there are other suggestions. Oulu was the capital of the Province of Oulu from 1776 to 2009.
In 1822, a major fire destroyed much of the city. The architect Carl Ludvig Engel, chiefly known for the neoclassical (empire style) buildings around Helsinki Senate Square, was enlisted to provide the plan for the rebuilding of the city. With minor changes, this plan remains the basis for the layout of Oulu's town center. The Oulu Cathedral was built in 1832 to his designs, with the spire being finished in 1844.
Once known for wood tar and salmon, Oulu has evolved into a major high-tech centre, particularly in IT and wellness technology. Other prominent industries include wood refining, paper, and steel. The University of Oulu is located six kilometers north of the city center. The Oulu Airport, located in the neighboring municipality of Oulunsalo, is the second busiest in Finland.
The municipality of Ylikiiminki was merged with the city of Oulu on January 1, 2009. Oulu and the municipalities of Haukipudas, Kiiminki, Oulunsalo and Yli-Ii will be merged on January 1, 2013.
The city is named after the river Oulujoki, which originates in the lake Oulujärvi. There have been a number of theories for the origin of the name Oulu. At minimum, the structure of the word requires that if originally given by speakers of a Uralic language, the name must be a derivative. In all likelihood it also predates Finnish settlement and is thus a
