| January 2 | Mozart's opera "Cosi fan tutti" premieres, Vienna |
| January 4 | President Washington delivers 1st State of the Union address |
| January 8 | George Washington delivers 1st state of union address |
| January 11 | Statisten and Vonckisten unite as Belgium |
| January 26 | Mozart's opera "Cosi Fan Tutte" premieres in Vienna |
| January 30 | Lifeboat 1st tested at sea, by Mr. Greathead, the inventor |
| February 1 | Supreme Court convenes for 1st time (New York City) |
| February 11 | Society of Friends petitions Congress for abolition of slavery |
| March 1 | 1st U.S. census authorized |
| March 13 | John Martin, 1st American-born actor, performs in Philadelphia |
| March 21 | Thomas Jefferson reports to President Washington in New York as Secretary of State |
| March 22 | Thomas Jefferson becomes the 1st U.S. Secretary of State |
| March 26 | Congress passes Naturalization Act, requires 2-year residency |
| March 27 | The shoelace invented |
| April 3 | Revenue Marine Service, U.S. Coast Guard, created |
| April 10 | Robert Gray is 1st American to circumnavigate the Earth |
| April 10 | U.S. Patent system forms |
| April 30 | Colonial troops occupy Bonni's marroon village |
| May 26 | Territory South of River Ohio created by Congress |
| May 29 | Rhode Is becomes last of original 13 colonies ratifying Constitution |
| May 31 | U.S. copyright law enacted |
| June 9 | 1st book copyrighted under constitution, "Philadelphia Spelling Book" |
| July 16 | Congress establishes District of Columbia |
| July 26 | U.S. passes Assumption bill making U.S. responsible for state debts |
| July 31 | 1st U.S. patent granted, to Samuel Hopkins for a potash process |
| August 1 | 1st U.S. census, population of 3,939,214 |
| August 4 | U.S. Coast Guard founded as Revenue Cutter Service |
| August 9 | Columbia returns to Boston after 3 year journey, 1st ship to carry U.S. flag around the world |
| August 10 | Robert Gray's Columbia, completes 1st American around world voyage |
| August 14 | Sweden and Russia sign Peace of Verela |
| October 28 | New York gives up claims to Vermont for $30,000 |
| November 11 | Chrysanthemums are introduced into England from China |
| December 2 | Austrian army occupies Brussels |
| December 6 | Congress meets in Philadelphia, new temporary U.S. capital |
| December 17 | Aztec calendar stone discovered in Mexico City |
| December 20 | 1st successful U.S. cotton mill to spin yarn (Pawtucket, RI) |
| December 22 | Russian troops occupy Ismail on Turks |
