Märket

Märket is a small 3.3-hectare uninhabited skerry in the Baltic Sea between Sweden and Finland, with a lighthouse as its salient manmade feature. Märket has been divided between the two countries since the Treaty of Fredrikshamn of 1809 defined the border between Sweden and the Russian Empire as going through the middle of the island. The Finnish side of the island is part of the Municipality of Hammarland and is the westernmost land point of Finland. The Swedish part of the island is itself divided by two counties of Sweden: Uppsala County and Stockholm County.