Wikipedia:Selected anniversaries/January 21
- 1789 – The Power of Sympathy by William Hill Brown, widely considered to be the first American novel, was published.
- 1919 – The First Dáil convened at the Mansion House in Dublin and adopted a declaration of independence calling for the establishment of the Irish Republic.
- 1941 – World War II: Sparked by the murder of a German officer on the previous day in Bucharest, Romania, members of the Iron Guard began a rebellion and pogrom.
- 1968 – Cold War: A B-52 bomber carrying four nuclear weapons crashed onto sea ice near Thule Air Base, Greenland, causing localized radioactive contamination.
- 1981 – The DeLorean Motor Company completed the first production car of the DMC DeLorean (example pictured).