Mariehamn is built on a part of the Åland islands where the distance on foot between the east and west coasts only takes about 15-20 minutes but in a boat you have to go a considerable distance around the south of the main island. The ferries from Stockholm to Turku on the Finnish mainland dock in Mariehamn on the west side and, with Viking Line at least, it's possible to go from either side for the day - although you would get virtually no time on shore.
Mariehamn is the capital of Åland, a province of Finland where the official language is Swedish, and the Parliament House is on the east side. In some ways it resembles a French provincial town but the sea dominates with the old fourmaster, the Pommern, providing a major atraction to the west. The combined ticket for the boat and the maritime museum is a good value.
The main Åland Museum is on the east at the south end and beyond it is very ageeable parkland next to the sea. [edit text][editors]