The estate of Grensholm held a private archive

Grensholm stood as a secure sanctuary for the personal archives of Gustaf Mannerheim. After winning over the reds in the civil war on May 16, 1918, Mannerheim spent a large part of the summer of 1918 at the estate. Between the Winter War and the Continuation War, he sent his private archives from a vault in the Bank of Finland to Grensholm to avoid them falling into the wrong hands. He continued to transport letters and notes to the location even after the end of the war for fear of a communist takeover. This repository became known as the Grensholmsarkivet, which Stig Jägerskiöld used for his biography of Mannerheim.

The estate possesses a long history of ownership through various sales and marriages. The main building likely dates to the second half of the 1600s and is currently built in a specific style. The site has been occupied since the medieval period, with a stone building from the 1500s that was later converted into a farm chapel. On the headland, one can find the ruins of Åls stenhus.

The grounds feature a park with a reflecting pond along with stone outbuildings constructed by dalkarlar in the mid 1700s. The Lagerfelt family owns the estate today. It continues to operate as an active farm while also serving as a center for conferences.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons