Tornio (Official name: Tornion kaupunki; in Northern Sami: Duortnus; in Swedish: Torneå) is a city and municipality in Lapland, Finland. The city forms a cross-border twin city together with Haparanda on the Swedish side. The municipality covers an area of 1,348.55 square kilometres (520.68 sq mi) of which 161.59 km2 (62.39 sq mi) is water. The population density is 18.79 inhabitants per square kilometre (48.7/sq mi), with a total population of 22,306 (30 June 2015).