It is located in the province of Western Finland and is part of the Southern Ostrobothnia region. The town has a population of 10,125 (30 June 2015) and covers an area of 1,056.75 square kilometres (408.01sqmi) of which 47.99km (18.53sqmi) is water. The population density is 10.04 inhabitants per square kilometre (26.0/sqmi).