February 22 – Christopher Seider, an 11-year-old boy in Boston at the British Province of Massachusetts Bay, is shot and killed by a colonial official, Ebenezer Richardson. The funeral sets off anti-British protests that lead to the massacre days later.
March 5 – Boston Massacre: Eleven American men are shot (five fatally) by British troops, in an event that helps start the American Revolutionary War five years later.
Date unknown -- Scottish scientist Daniel Rutherford discovers nitrogen gas, isolating it from air.
July 1 – Lexell's Comet (D/1770 L1) passes the Earth at a distance of 2184129 km, the closest approach by a comet in recorded history.
April 29 – First voyage of James Cook: Captain Cook drops anchor on HMS Endeavour in a wide bay, about 16 km (10 mi) south of the present city of Sydney, Australia. Because the young botanist on board the ship, Joseph Banks, discovers 30,000 specimens of plant life in the area, 1,600 of them unknown to European science, Cook names the place Botany Bay on May 7.
January 10 – American Revolution – Thomas Paine publishes his pamphlet Common Sense ("written by an Englishman" in Philadelphia), arguing for independence from British rule in the Thirteen Colonies.
March 9 – Scottish economist Adam Smith publishes The Wealth of Nations in London.
September 6 – A hurricane hits Guadeloupe, killing more than 6,000 people
September 9 – The Continental Congress officially names its union of states the United States.
October 31 – In his first speech before British Parliament since the Declaration of Independence that summer, King George III acknowledges that all is not going well for Britain, in the war with the United States.