September 3 is the 246th day of the year (247th in leap years). There are 119 days remaining.
- 1658: Oliver Cromwell
- 1970: Vince Lombardi, American football coach
- 1991: Frank Capra, Movie director
- 1189: England's King Richard I was crowned in Westminster.
- 1783: Treaty of Paris signed, ending the revolutionary war between the US and Great Britain.
- 1943: Italy invaded by the Allied forces during World War II.
- 1976: The US spacecraft Viking 2 landed on Mars.