The Österbybruk was established by the King Gustav Vasa in the 16th century. Int 1643 it was acquired by Louis de Geer and in his time Österbybruk became the center of weapon manufacturing in Sweden. Later it was owned by Grill and Tamm families.
The manor house of Österbybruk was built in 1763-1780 by the design of Elias Kessler and Erik Palmstedt. There is also a Calvinist church with a mirror hall built in 1735. The industrial milieu with labour cottages, workshops and magazines surrounding the manor is well-preserved.References:
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.