Ähtäri (Swedish:Etseri) is a town and municipality of Finland.
It is located in the Southern Ostrobothnia region. The town has a population of 6,155 (30 June 2015) and covers an area of 909.96 square kilometres (351.34sqmi) of which 105km (41sqmi) is water. The population density is 7.65 inhabitants per square kilometre (19.8/sqmi).