Somero (Finnish pronunciation: [ˈsomero]) is a municipality of Finland, located in the province of Western Finland and part of the Southwest Finland region. The municipality has a population of 9,147 (30 June 2015) and covers an area of 697.68 square kilometres (269.38 sq mi) of which 29.9 km2 (11.5 sq mi) is water. The population density is 13.7 inhabitants per square kilometre (35/sq mi). Somero is unilingually Finnish.