Märket lighthouse

Märket is a 3.3-hectare (8.2-acre) uninhabited skerry in the Baltic Sea shared by Sweden and Finland, with a lighthouse as its salient humanmade feature. Märket has been divided between the two countries since the Treaty of Fredrikshamn of 1809 defined the border between Sweden and Grand Duchy of Finland as going through the middle of the island. The Finnish side of the island is part of the Municipality of Hammarland in the autonomous region of Åland and is the westernmost land point of Finland. The Swedish part of the island is itself divided between two counties of Sweden: Uppsala County and Stockholm County.