Haapavesi is a town and a municipality of Finland. It is located in the North Ostrobothnia region. The name means "Aspen Water". The town has a population of 6,404 and covers an area of 1,086.11 square kilometres of which 36.41 km2 is water. The population density is 6.1 inhabitants per square kilometre. Neighbour municipalities are Haapajärvi, Kärsämäki, Nivala, Oulainen, Raahe, Siikalatva and Ylivieska. The municipality is unilingually Finnish.