The small Grisslehamn village is today a well-preserved sample of 19th century architecture and popular attraction for daily trips. The name Grisslehamn was first mentioned in a document from 1376 about the mail route between Sweden and Finland. This Grisslehamn was located some 20 km south of today's location. In the mid-18th century, most of the old village was destroyed in a fire, and it was decided to move Grisslehamn to its current location to make the mail route shorter. Conveying mail by row boat from Sweden to Åland, from whence it was transported to the Finnish mainland, was, together with fishing, one of the most important sources of income for the inhabitants of Grisslehamn and other parts of Roslagen for a long time, until steam ships took over the mail routes in the early 20th century.
During the Finnish War in 1809 a small unit of Russian cossacks attacked to Grisslehamn over the frozen Gulf of Bothnia. In the battle 80 Swedish soldiers surrended and several were killed.
Today there are several buildings dating from the 19th century, like the toll station and old barracks. The post office was built in 1755 and the chapel in 1909.References:
Ängsö Castle was first named as "Engsev" in a royal charter by king Canute I of Sweden (r. 1167-1196), in which he stated that he had inherited the property after his father Eric IX of Sweden. Until 1272, it was owned by the Riseberga Abbey, and then taken over by Gregers Birgersson.
From 1475 until 1710, it was owned by the Sparre family. The current castle was built as a fortress by riksråd Bengt Fadersson Sparre in the 1480s. In 1522, Ängsö Castle was taken after a siege by king Gustav Vasa, since its owner, Fadersson's son Knut Bengtsson, sided with Christian II of Denmark. However, in 1538 it was given by the king to Bengtsson's daughter Hillevi Knutsdotter, who was married to Arvid Trolle.
In 1710, the castle was taken over by Carl Piper and Christina Piper. Ängsö Castle was owned by the Piper family from 1710 until 1971, and is now owned by the Westmanna foundation. The castle building itself was made into a museum in 1959 and was made a listed building in 1965. It is currently opened to visitors during the summers.
The castle is a cubical building in four stores made by stone and bricks. The lower parts is preserved from the middle ages. It was redecorated and expanded in the 1630s. The 4th storey as well as the roof is from the expansion of Carl Hårleman from 1740-41. It gained its current appearance in the 1740s.