| January 1 | Giuseppe Piazzi discovers 1st asteroid, which is named Ceres later |
| January 1 | Ireland and Great Britain, England and Scotland, form United Kingdom |
| January 1 | United Kingdom of Great Britain and Ireland established |
| January 20 | John Marshall appointed U.S. chief justice |
| February 9 | France and Austrian sign Peace of Luneville |
| February 17 | House breaks electoral college tie, chooses Jefferson President over Burr |
| February 27 | Washington D.C. placed under Congressional jurisdiction |
| March 3 | 1st U.S. Jewish governor, David Emanuel, takes office in Georgia |
| March 4 | Thomas Jefferson is the 1st president inaugurated in Washington D.C. |
| March 7 | Massachusetts enacts 1st state voter registration law |
| March 8 | British drive French forces from Abukir, Egypt |
| March 23 | Murder attempt on Czar Paul I |
| March 24 | Aleksandr P Romanov becomes emperor of Russia |
| April 8 | Soldiers riot in Bucharest, kill 128 Jews |
| April 11 | Johann von Schiller's "Die Jungfrau von Orleans," premieres in Leipzig |
| April 24 | 1st performance of Joseph Haydn's oratorio "Die Jahreszeiten" |
| June 6 | Peace of Badajoz: Spain-Portugal |
| June 10 | Tripoli declares war on U.S. for refusing tribute |
| July 6 | Battle at Algeciras: French fleet beats British |
| July 7 | Toussaint L'Ouverture declares Haitian independence |
| July 11 | French astronomer Jean-Louis Pons discovers his 1st comet |
| July 12 | Battle at Algeciras: British fleet beats French and Spanish |
| July 16 | Pope Pius VII and 1st consul Napoleon sign concord |
| July 20 | Elisha Brown, Jr. pressed a 1,235 pound cheese ball at his farm |
| October 1 | England and France signs Preliminary of London |
| November 10 | Kentucky outlaws dueling |
| November 16 | 1st edition of New York Evening Post |
