The Masku Church, built probably in 1490-1510, and surroundings represents one of the oldest parishes in Western Finland. The Masku parish was mentioned first time in 1234. The Mural paintings and pulpit date from the 17th century. There are also several medieval artefacts like crucifix and Silesian altarpiece located inside the church. Near the church is also "Humikkalan kalmisto", an Iron Age burial ground.
Finnish National Board of Antiquities has described the church area as national built heritage.
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.