Kauhajoki is a town and municipality of Finland. It is located in the province of Western Finland and is part of the Southern Ostrobothnia region, 59 kilometres southwest of the city of Seinäjoki. The population of Kauhajoki is 12,618 and the municipality covers an area of 1,298.98 km2 of which 16.46 km2 is inland water. The population density is 9.71/km2. The town is unilingually Finnish.