Historical events in 1780
- A blizzard hit Washington's army at the Morristown, NJ, winter encampment.
- Pennsylvania became the first U.S. state to abolish slavery (for new-borns only). It was followed by Connecticut and Rhode Island in 1784, New York in 1785, and New Jersey in 1786. Massachusetts abolished slavery through a judicial decision in 1783.
- The 1st British Sunday newspaper appeared as the British Gazette and Sunday Monitor.
