Seinäjoki is a city in Finland and the regional capital of South Ostrobothnia. Seinäjoki is located in the western interior of the country and along the River Seinäjoki. The population of Seinäjoki is approximately 67,000, while the sub-region has a population of approximately 132,000. It is the 16th most populous municipality in Finland, and the 13th most populous urban area in the country.