2nd January » Big Bottom massacre in the Ohio Country, marking the beginning of the Northwest Indian War.
25th January » The Parliament of Great Britain British Parliament passes the Constitutional Act of 1791 and splits the old Province of Quebec (1763–1791) Province of Quebec into Upper Canada Upper and Lower Canada.
2nd March » Long-distance communication speeds up with the unveiling of a semaphore line named semaphore machine in Paris.
4th March » The Constitutional Act of 1791 is introduced by the House of Commons of the United Kingdom named British House of Commons in London which envisages the separation of Canada into Lower Canada (Quebec) and Upper Canada (Ontario).
4th March » Vermont is admitted to the United States as the fourteenth U.S. state known as state.
3rd May » The Constitution of May 3, 1791 or Constitution of May 3 (the first modern constitution in Europe) is proclaimed by the Sejm of Polish–Lithuanian Commonwealth.
15th May » French Revolution: Maximilien Robespierre proposes the Self-denying Ordinance (French Revolution) named Self-denying Ordinance.
21st June » King Louis XVI of France and his immediate family begin the Flight to Varennes during the French Revolution.
14th July » The Priestley Riots drive Joseph Priestley, a supporter of the French Revolution, out of Birmingham, England.
17th July » Members of the National Guard (France) French National Guard under the command of Gilbert du Motier, marquis de Lafayette General Lafayette Champ de Mars Massacre open fire on a crowd of radical Jacobin (politics) Jacobins at the Champ de Mars, Paris, dur
4th August » The Treaty of Sistova is signed, ending the Ottoman–Habsburg wars.
7th August » American troops destroy the Miami people known as Miami town of Battle of Kenapacomaqua known as Kenapacomaqua near the site of present-day Logansport, Indiana in the Northwest Indian War.
22nd August » Beginning of the Haitian Haitian Revolution or Slave Revolution in Saint-Domingue.
26th August » John Fitch (inventor) e.g John Fitch is granted a United States patent for the steamboat.
30th August » HMS Pandora 1779 6 sinks after having run aground on a reef the previous day.
9th September » Washington, D.C., the capital of the United States, is named after President George Washington.
13th September » King Louis XVI of France accepts the French Constitution of 1791 named new constitution.
14th September » The Papal States lose Avignon to the First French Empire e.g French Empire.
28th September » France becomes the first country to Jewish emancipation named emancipate its Jewish population.
30th September » The first performance of 'The Magic Flute', the last opera by Wolfgang Amadeus Mozart or Mozart to make its debut, took place at Freihaus-Theater auf der Wieden in Vienna, Austria.
30th September » The National Constituent Assembly in Paris is dissolved; Parisians hail Maximilien Robespierre and Jérôme Pétion as "incorruptible patriots".
1st October » First session of the French Legislative Assembly (France) e.g Legislative Assembly.
9th November » Foundation of the Dublin Society of United Irishmen.
15th November » The first U.S. Catholic college, Georgetown University, opens its doors.
15th December » The United States Bill of Rights becomes law when ratified by the Virginia General Assembly.