1784

thumb|250px|[[March 22: The Emerald Buddha is installed at the Wat Phra Kaew]]

Events

January 6 – Treaty of Constantinople: The Ottoman Empire agrees to Russia's annexation of the Crimea.
January 14 – The Congress of the United States ratifies the Treaty of Paris with Great Britain to end the American Revolution, with the signature of President of Congress Thomas Mifflin.
January 15 – Henry Cavendish's paper to the Royal Society of London, Experiments on Air, reveals the composition of water.
February 24 – The Captivity of Mangalorean Catholics at Seringapatam begins.
February 28 – John Wesley ordains ministers for the Methodist Church in the United States.
March 1 – The Confederation Congress accepts Virginia's cession of all rights to the Northwest Territory and to Kentucky (Illinois County).
April 27 – The Marriage of Figaro, written by playwright Pierre Beaumarchais as a sequel to The Barber of Seville, premieres at the Comédie-Française in Paris.
May 12 – The Treaty of Paris, signed on September 3 the previous year, comes into effect.
May 20 – A treaty is signed in Paris between the Kingdom of Great Britain and the Dutch Republic, formally ending the Fourth Anglo-Dutch War.
June 4 – Élisabeth Thible is the first woman to ascend in a hot-air balloon, at Lyon, France.

July 9 – The Bank of New York opens as the first in New York state and continues to operate under that name for almost 223 years until being acquired by Mellon Financial and becoming BNY Mellon.
July 29 – The United States and the Kingdom of France sign a convention for establishing diplomatic relations and "determining the functions and prerogatives of their respective consuls, vice consuls, agents, and commissaries".
August 13 – Parliament of Great Britain passes Pitt's India Act (An Act for the better Regulation and Management of the Affairs of the East India Company and of the British Possessions in India). It requires the governor-general to be chosen from outside the Company and makes company directors subject to parliamentary supervision.
August 16 – Britain creates the colony of New Brunswick.
September 19 – In France, the Robert brothers (Anne-Jean Robert and Nicolas-Louis Robert) and a Mr. Collin-Hullin (whose first name is lost to history) become the first people to fly more than 100 km or 100 miles in the air, lifting off from Paris and landing 6 hours and 40 minutes later near Bethune after a journey of .
September 22 – Russia establishes a colony at Kodiak, Alaska.

October 8 – "Kettle War", a 1-day action on the Scheldt in which a ship of the Dutch Republic repels forces of the Holy Roman Empire.
October 22 – North Carolina rescinds its resolution ceding its western territory (Washington District, modern-day Tennessee) to the United States, after earlier giving Congress two years to accept the terms.
November 30 – Richard Henry Lee of Virginia is selected as the new President of the Confederation Congress.

thumb|right|110px|[[Denis Diderot]]

July 31 – Denis Diderot, French philosopher, encyclopedist (b. 1713)
August 4 – Giovanni Battista Martini, Italian musician (b. 1706)
August 10 – Allan Ramsay, Scottish portrait-painter (b. 1713)
August 14 – Nathaniel Hone, Irish-born painter (b. 1718)
August 28 – Junípero Serra, Spanish Franciscan missionary (b. 1713)
September 1 – Jean-François Séguier, French astronomer and botanist (b. 1703)
September 4 – César-François Cassini de Thury, French astronomer (b. 1714)
September 8 – Ann Lee, American religious leader (b. 1736)
September 15 – Nicolas Bernard Lépicié, French painter (b. 1735)
November 1 – Jean-Jacques Lefranc, Marquis de Pompignan, French polymath, author and poet (b. 1709)
November 9 – George Baylor, officer in the American Continental Army (b. 1752)
December 5 – Phillis Wheatley, first published African-American author (b. 1753)

thumb|right|110px|[[Samuel Johnson]]

December 13 – Samuel Johnson, English writer, lexicographer (b. 1709)
December 25 – Yosa Buson, Japanese poet, painter (b. 1716)
December 26 – Seth Warner, American revolutionary leader (b. 1743)
date unknown – Raja Haji Fisabilillah, Buginese monarch of the Johor Sultanate, warrior, emperor, and government official
date unknown – Abd al-Karim Kashmiri, Indo-Persian historian