| January 11 | Michigan Territory organizes |
| March 3 | Louisiana-Missouri Territory forms |
| April 7 | Premiere of Beethoven's "Eroica" (conducted by himself) |
| April 27 | U.S. Marines attack shores of Tripoli |
| May 4 | Henry C. Overing buys 80 acres of Throggs Neck in Bronx |
| May 26 | Lewis and Clark 1st see Rocky Mountains |
| May 26 | Napoleon is crowned king of Italy |
| June 4 | Tripoli forced to conclude peace with U.S. after war over tribute |
| June 5 | 1st recorded tornado in "Tornado Alley", Southern Illinois |
| June 21 | Great Stoneface Mount found in New Hampshire |
| July 8 | American Bill Richmond knocks out Jack Holmes, Kilburn Wells, England |
| July 26 | Naples/Calabria struck by Earthquake; about 26,000 die |
| September 4 | 1st edition of Batavian State-Current published |
| September 30 | Napoleons army draws into the Rhine |
| October 21 | Battle of Trafalgar, Admiral Nelson defeats French and Spanish fleet and dies |
| October 23 | Sailing ship "Aeneus" sinks off Newfoundland killing 340 |
| November 7 | Lewis and Clark 1st sights Pacific Ocean |
| November 16 | Battle at Schongrabern: Russian army stop French |
| November 18 | 30 women meet at Mrs. Silas Lee's home in Wiscasset Maine, organizes |
| November 18 | Female Charitable Society, first woman's club in America |
| November 20 | Beethoven's "Fidelio," premieres in Vienna |
| November 24 | Lewis and Clark reach Pacific Ocean, 1st Americans to cross continent |
| November 25 | Opera "Thais" 1st American performance |
| December 2 | Napoleon defeats Russians and Austrians at Austerlitz |
| December 9 | Comet 3D/1805 V1 (Biela) approaches within 0.0366 AUs of Earth |
| December 26 | France and Austria signs Peace of Pressburg |
| December 26 | Pennsylvania Academy of Fine Arts established, Philadelphia |
| December 31 | End of French Republican calendar; France returns to Gregorianism |
BrainyHistory
