* January 2 - George Washington takes office as the first President of the United States.
* February 13 - The Patent Act of 1790 is passed, creating the United States Patent and Trademark Office.
* March 22 - The District of Columbia is established as the permanent capital of the United States.
* May 12 -Rhode Island becomes the 13th state to ratify the United States Constitution.
* June 8 - The United States Mint is established in Philadelphia.
* July 16 - The first United States Census is conducted.
1791
* January 1 - The Bank of the United States is chartered.
* March 4 - Vermont becomes the 14th state to join the United States.
* April 25 - The first federal income tax is enacted.
* May 10 - The Bill of Rights is ratified, adding ten amendments to the United States Constitution.
* June 1 - The Whiskey Rebellion begins in western Pennsylvania.
* August 20 - The Whiskey Rebellion is suppressed by federal troops.
* December 15 - The Bill of Rights goes into effect.
1792
* January 1 - President Washington issues the Neutrality Proclamation, declaring that the United States will remain neutral in the war between France and Great Britain.
* March 1 - Kentucky becomes the 15th state to join the United States.
* April 12 - The United States Mint begins operations in Philadelphia.
* June 1 - The Alien and Sedition Acts are passed, allowing the government to deport immigrants who are deemed to be a threat to the United States and to prosecute people who criticize the government.
* December 5 - George Washington is reelected as President of the United States.
1793
* January 22 - France declares war on Great Britain and the Netherlands, beginning the War of the First Coalition.
* March 4 - George Washington begins his second term as President of the United States.
* April 22 - The United States declares its neutrality in the War of the First Coalition.
* June 1 - The Fugitive Slave Act is passed, allowing slave owners to reclaim slaves who have escaped to free states.
* July 31 - Eli Whitney patents the cotton gin, revolutionizing the cotton industry in the United States.
* September 18 - Yellow fever breaks out in Philadelphia, killing thousands of people.
1794
* January 1 - The French begin to seize American ships that are trading with Great Britain.
* March 26 - The United States and Great Britain sign the Jay Treaty, resolving some of the disputes between the two countries.
* April 7 - The Whiskey Rebellion is suppressed by federal troops.
* May 31 - The Eleventh Amendment to the United States Constitution is ratified, limiting the ability of citizens to sue states.
* July 4 - The Fourth of July is celebrated for the first time as a federal holiday.
* December 31 - George Washington retires from the presidency.
1795
* January 1 - John Adams is inaugurated as the second President of the United States.
* February 19 - The United States and Great Britain sign the Pinckney's Treaty, resolving the dispute over the boundary between the United States and Spanish Florida.
* April 7 - The United States and France sign the Treaty of Paris, ending the Quasi-War.
* October 27 - The United States and Spain sign the Treaty of San Lorenzo, resolving the dispute over the boundary between the United States and Spanish Florida.
* November 1 - Ohio becomes the 17th state to join the United States.
1796
* March 4 - John Adams is reelected as President of the United States.
* April 30 - The United States and France sign the Convention of 1800, which ends the Quasi-War and establishes peace between the two countries.
* July 4 - The Fourth of July is celebrated for the first time in the District of Columbia.
* December 15 - The Twelfth Amendment to the United States Constitution is ratified, changing the way that the President and Vice President are elected.
1797
* January 22 - John Adams delivers the first State of the Union Address to Congress.
* March 4 - Thomas Jefferson is inaugurated as the third President of the United States.
* April 18 - The United States declares war on Tripoli, beginning the First Barbary War.
* May 24 - The British ship _HMS Leopard_ attacks the American ship _USS Chesapeake_ off the coast of Virginia.
* June 6 - The United States declares war on Great Britain, beginning the War of 1812.
* August 16 - The Battle of Tippecanoe is fought between the United States Army and the Shawnee Indians.
* October 25 - The United States and Great Britain sign the Treaty of Ghent, ending the War of 1812.
* December 24 - The Hartford Convention is held, at which delegates from New England discuss the possibility of seceding from the United States.
1799
* February 22 - George Washington dies at the age of 67.
* March 4 - Thomas Jefferson is reelected as President of the United States.
* April 30 - The United States acquires the Louisiana Territory from France.
* June 18 - The Lewis and Clark Expedition begins.
* September 11 - Hurricane San Ciriaco strikes Puerto Rico, killing thousands of people.
* December 14 - The Electoral College meets and elects Thomas Jefferson and Aaron Burr as President and Vice President, respectively.
* December 31 - The House of Representatives votes to elect Thomas Jefferson as President and Aaron Burr as Vice President.