Oulu ( ) (Uleåborg) is a city and municipality of about 130,000 inhabitants in the province of Oulu and the region of Northern Ostrobothnia, in Finland. It is the largest and most important city in Northern Finland and the sixth largest city in the country. Its population growth rate is almost comparable with that of the Helsinki Metropolitan Area. Oulu has a namesake in the United States, Oulu, Wisconsin, which is a village with a population of about 540.