- 1801 - Legislative union of Great Britain and Ireland completed
- 1863 - Abraham Lincoln delivers the Emancipation Proclamation during the second year of the American Civil War.
- 1892 - Ellis Island opens to begin accepting immigrants to the United States.
- 1901 - Establishment of the Commonwealth of Australia (Federation)
- 1970 - Unix epoch begins at 00:00:00 UTC.
- 1984 - Brunei becomes a fully independent state
- 1431 - Rodrigo Borgia (Pope Alexander VI)
- 1735 - Paul Revere, silversmith, United States patriot
- 1752 - Betsy Ross, seamstress
- 1879 - E. M. Forster, novelist
- 1895 - J. Edgar Hoover, FBI director
- 1909 - Barry M. Goldwater, Arizona Senator
- 1911 - Hank Greenberg, baseball player
- 1919 - J. D. Salinger, novelist
- 1921 - Rocky Graziano, boxer, born "Rocky Barbella"
- 1940 - Frank Langella, actor
- 1942 - Country Joe McDonald (of Country Joe and the Fish fame)
- 2001 - Ray Walston, 86, actor best known as the star of TV's My Favorite Martian, and later as a judge on Picket Fences.
Holidays and observances:
- United States - New Year's Day
- United States - Copyright Expiration Day, celebrating the expiration of the copyright of a year's worth of works of authorship into the public domain. Not celebrated from 1978 to 2018 because of repeated copyright term extensions.