Addition to the border treaty of 1751 between Sweden (including Finland) and Norway (Denmark-Norway).

1751 Massacre of British-Canadians during Father Le Loutre's War

On May 21, 1751, a magnitude 7.0–7.4 earthquake struck near Takada in present-day Jōetsu City, Niigata Prefecture, Japan, causing significant damage and resulting in approximately 2,100 fatalities

1751 battle during the Second Carnatic War