President:
Pres: (Continental Congress) Samuel Huntington
General
- Crime: Benedict Arnold's plot to surrender West Point is revealed
- Politics: Franklin named Ambassador to France
- Revolution: War continues
East
- General: "The Hard Winter" of 1780 freezes over New England as far south as NY and NJ
- Connecticut: Lemuel Haynes preaches, the first black preacher of a mostly white congregation
- Massachusetts: Constitution written
American Academy of Sciences founded at Boston
- New Jersey: Americans defeated at Camden
- New York: General Washington and troops stalled in major snowstorm at Morristown
British block Washington's attempt to retake New York
- Pennsylvania: Gradual emancipation law enacted
- Rhode Island: 5000 French troops arrive at Newport
Midwest
- General: Smallpox outbreak on the US plains
South
- Florida: Spanish forces recapture west FL from Britain
- North Carolina: British army defeated at King's mountain
- South Carolina: Charleston surrenders to British