Mariehamn is the capital of Åland, an autonomous territory under Finland's sovereignty. Mariehamn has 10,632 inhabitants on an area of 11 km² (2003), almost half of the population of Åland lives there. Mariehamn, founded in 1861, was named after the Tsaritsa Maria Alexandrovna.

Mariehamn is the seat of the Government of Åland and the Parliament of Åland.

On maps and in Finnish statistics, the town's name may exceptionally appear as Maarianhamina (Finnish language). The municipality of Mariehamn is, like all of Åland, unilingually Swedish.

de:Mariehamn pl:Maarianhamina fi:Maarianhamina sv:Mariehamn