1797

January–March

• January 3 - The Treaty of Tripoli, a peace treaty between the United States and Ottoman Tripolitania, is signed at Algiers.
• January 7 - The parliament of the Cisalpine Republic adopts the Italian green-white-red tricolour as their official flag.
• January 13 - Action of 13 January 1797, part of the War of the First Coalition: Two British Royal Navy frigates, HMS Indefatigable and HMS Amazon, drive the French 74-gun ship of the line Droits de l'Homme aground on the coast of Brittany, resulting in over 900 deaths.
• January 14 - War of the First Coalition - Battle of Rivoli: French forces under General Napoleon Bonaparte defeat an Austrian army of 28,000 men, under Feldzeugmeister József Alvinczi, near Rivoli, ending Austria's fourth and final attempt to relieve the fortress city of Mantua.
• January 26 - The Treaty of the Third Partition of Poland is signed in St. Petersburg by the Russian Empire, Austria and the Kingdom of Prussia.
• February 2 - Siege of Mantua: Field marshal Dagobert von Wurmser surrenders the fortress city to the French; only 16,000 men of the garrison are capable of marching out as prisoners of war.
• February 3 - Battle of Faenza: A French corps under General Claude Victor-Perrin defeats the forces from the Papal States, at Castel Bolognese near Faenza, Italy.
• February 4 - The Riobamba earthquake in Ecuador, estimated magnitude 8.3, causes up to 40,000 casualties.
• February 12 - "Gott erhalte Franz den Kaiser" is first performed, with the music composed in January by Joseph Haydn, which also becomes the tune to the Deutschlandlied, the German national anthem.
• February 14 - French Revolutionary Wars - Battle of Cape St. Vincent: The British Royal Navy under Admiral Sir John Jervis defeats a larger Spanish fleet off Cape St. Vincent, Portugal.
• February 18 - Invasion of Trinidad: Spanish Governor José María Chacón peacefully surrenders the colony of Trinidad to a British naval force, commanded by Sir Ralph Abercromby.
• February 19 - Treaty of Tolentino: Pope Pius VI signs a peace treaty with Revolutionary France. He is forced to deliver works of art, treasures, territory, the Comtat Venaissin and 30 million francs.
• February 22 - The last invasion of Britain begins: French forces, under the command of American Colonel William Tate, land near Fishguard, Wales.
• February 25 - William Tate surrenders to the British at Fishguard.
• February 26 - Bank Restriction Act removes the requirement for the Bank of England to convert banknotes into gold – Restriction period lasts until 1821. The Bank of England issues the first one-pound and two-pound notes.
• March 5 - Protestant missionaries from the London Missionary Society land in Tahiti, from the Duff.
• March 13 - Médée, an opera by Luigi Cherubini, is premiered in Paris.
• March 16 - Battle of Valvasone: The Austrian army, led by Archduke Charles, fights a rearguard action at the crossing of the Tagliamento River, but is defeated by Napoleon Bonaparte at Valvasone.
• March 21 - Battle of Parramatta: Resistance leader Pemulwuy leads a group of aboriginal warriors, estimated to be at least 100, in an attack on a government farm at Toongabbie in Sydney, Australia.

  April–June

• April 16 - The Spithead and Nore mutinies break out in the British Royal Navy.
• April 17
• * Battle of San Juan: Sir Ralph Abercromby unsuccessfully invades San Juan, Puerto Rico in what will be one of the largest British attacks on Spanish territories in the western hemisphere, and one of the worst defeats of the British Royal Navy for years to come.
• * Veronese Easter: Citizens of Verona, Italy, began an unsuccessful eight-day rebellion against the French occupying forces.
• April 18 - Armistice of Leoben: On behalf of the French Republic, a delegation under Napoleon Bonaparte signs a peace treaty with the Holy Roman Empire at Leoben.
• May 10 - The first ship of the United States Navy, the frigate USS United States, is commissioned.
• May 12 - War of the First Coalition: Napoleon Bonaparte conquers Venice, ending the city and Republic of Venice's 1,100 years of independence. The last doge of Venice, Ludovico Manin, steps down. The Venetian Ghetto is thrown open.
• May 30 - English abolitionist William Wilberforce marries Barbara Ann Spooner about six weeks after their first meeting.
• June 28 - French troops disembark in Corfu, beginning the First period of French rule in the Ionian Islands.
• June 29 - Napoleon Bonaparte decrees the birth of the Cisalpine Republic; he appoints ministers and establishes the first constitution.

  July–September

• July 9 - U.S. Senator William Blount becomes the first federal legislator to be expelled from office, as his fellow Senators vote 25 to 1 to block him from his seat during an investigation against him on charges of criminal conspiracy.
• July 13 - Gual and España conspiracy against Spanish rule in Colonial Venezuela is exposed.
• July 24 - Horatio Nelson is wounded at the Battle of Santa Cruz, losing an arm.
• August 29 - Massacre of Tranent: British troops attack protestors against enforced recruitment into the militia at Tranent, Scotland, killing 11 and injuring 8.
• September 4 - The Coup of 18 Fructidor is carried out in France as three of the five members of The Directory, France's executive council, arrested royalist members of the Council of Five Hundred, the national legislature, and discard the results of the spring elections.
• September 5 - France's new government decrees that citizens who left the country without authorization are subject to the death penalty if they return.
• September 30 - Dominique-Vincent Ramel-Nogaret, French finance minister, repudiates two thirds of France's debt.

  October–December

• October 11 - Battle of Camperdown: the British Royal Navy defeats the fleet of the Batavian Republic off the coast of Holland.
• October 17 - The Treaty of Campo Formio ends the War of the First Coalition.
• October 18 - The XYZ Affair inflames tensions between France and the United States when American negotiators Charles Cotesworth Pinckney, John Marshall, and Elbridge Gerry meet with French government representatives Jean-Conrad Hottinguer, Pierre Bellamy and Lucien Hauteval and are told that a treaty between France and the U.S. will require payment of a bribe to France's Foreign Minister Charles Talleyrand and a large loan of American cash to France. Pinckney tells people later that his response was "No, no, not a sixpence!"; Hottinguer, Bellamy and Hauteval are referred to, respectively, as "X", "Y" and "Z" in U.S. government reports on the failed negotiations.
• October 21 - In Boston Harbor, the 44-gun United States Navy frigate is launched to fight Barbary pirates off the coast of Tripoli; the ship will remain in commission in the 21st century.
• October 22 - André-Jacques Garnerin makes the first parachute descent, at Parc Monceau, Paris; he uses a silk parachute to descend approximately from a hot air balloon.
• November - 1797 Rugby School rebellion: The students at Rugby School in England rebel against the headmaster, Henry Ingles, after he decrees that the damage to a tradesman's windows should be paid for by the students.
• November 16
• * The Prussian heir apparent, Frederick William, becomes King of Prussia as Fredrick William III.
• * - British Royal Navy frigate is wrecked on the approaches to Halifax, Nova Scotia; of the 240 on board, all but 12 are lost.

  Undated

• The secret Lautaro Lodge as the Logia de los Caballeros Racionales is founded, perhaps in Cádiz; membership will include many leaders of the Spanish American wars of independence such as Francisco de Miranda, Bernardo O'Higgins and José de San Martín.
• Shinyukan Cram School founded by Masataka Okudaira in Nakatsu, Buzen Province, Kyushu Island, as predecessor of Keio-Gijyuku University in Japan.
• Joseph-Louis Lagrange publishes his treatise on differential calculus, entitled Théorie des fonctions analytiques.