The Great Plague of 1710–1711 was a devastating event in Finland's history, occurring during the larger context of the Great Northern War (1700–1721). Originating from Central Asia, the plague followed trade and military routes, spreading to various parts of Europe, including Finland, which was then an integral part of the Swedish Empire. By 1710, ships carrying the plague arrived in Finland from Reval (Tallinn), spreading rapidly across the country.
Helsinki (Helsingfors) was among the first Finnish cities to be hit, losing two-thirds of its population, as 1,185 people died. The plague spread further to Borgå (Porvoo), where 652 people perished, and then reached other major coastal towns like Åbo (Turku), where 2,000 people died, significantly reducing the population. The epidemic also struck smaller towns and rural areas throughout Finland, reaching as far north as Kajaani.
The plague, along with other diseases and famine, decimated Finland's population, killing a substantial portion of its inhabitants. Contemporary responses to the plague were rudimentary, with people relying on measures like quarantining infected areas, lighting fires to purify the air, and fleeing the affected regions. The plague eventually subsided by 1712, but it left a lasting impact on Finland, both demographically and socially, contributing to the larger hardships endured during the war and the resulting Russian occupation.