Laihia (Swedish: Laihela) is a municipality of Finland, founded in 1576 through a separation from Isokyrö and Korsholm. It is located in the province of Western Finland and is a part of the Ostrobothnia region. The municipality has a population of 8,064 (30 November 2014) and covers an area of 508.38 square kilometres (196.29 sq mi) of which 4.14 km² (1.60 sq mi) is water. The population density is 15.99 inhabitants per square kilometre (41.4/sq mi).