Haapajärvi

Haapajärvi (Finnish:) is a town and municipality of Finland.

It is located in the province of Oulu and is part of the Northern Ostrobothniaregion. The town has a population of 6,441 (31 December 2025) and covers an area of 789.11 square kilometres (304.68 sq mi) of which 23.44 km (9.05 sq mi) is water. The population density is 8.4 inhabitants per square kilometre (22/sq mi).

Neighbour municipalities are Haapavesi, Kärsämäki, Nivala, Pihtipudas, Pyhäjärvi, Reisjärvi and Sievi.

The municipality is unilingually Finnish.