The first evidence of Pyhtää as an independent parish dates back to 1380. At that time already the parish had a church, but it is not known where it was situated or what it looked like. Until 1600 Pyhtää included, besides its present area, also half of the present city of Kotka, Ruotsinpyhtää, Elimäki, the western parts of Anjalankoski, and a part of Lapinjärvi.
Dedicated to St. Henry, the church is situated where one of the westernmost branches of the river Kymi meets the ancient Turku-Viipuri coast road.
The building resembles the majority of the Finnish medieval stone churches. Pyhtää church, built about 1460, has retained its original medieval appearance almost untouched. There have been few alterations: the porch was converted into a memorial choir during the latter half of the 18th century, and in connection with repairs in 1907, buttresses were built to support the north wall and the sacristy was fitted with the outer entrance.
Frösöstenen is the northern-most raised runestone in the world and Jämtland's only runestone. It originally stood at the tip of ferry terminal on the sound between the island of Frösön and Östersund. The stone dates to between 1030 and 1050. It has now been relocated to the lawn in front of the local county seat due to the construction of a new bridge, between 1969 and 1971, on the original site.
Frösö runestone inscription means: Austmaðr, Guðfastr's son, had this stone raised and this bridge built and Christianized Jämtland. Ásbjörn built the bridge. Trjónn and Steinn carved these runes.