Events of 1784

January–June

• January 6 – The Turks agree to Russia's annexation of the Crimea in the Treaty of Constantinople.

• January 14 – The US Congress ratifies the Treaty of Paris with Great Britain to end the American Revolutionary War.

• February 27 – The Count of St. Germain dies of pneumonia in Schleswig-Holstein.

February 28: John Wesley charters the Methodist Church.

• February 28 – John Wesley charters the Methodist Church.

• June 4 – Elisabeth Thible is the first woman to ride in a balloon.

July–December

• August 15 – Cardinal de Rohan is called before the court to account for his actions in the Queen's Necklace Affair.

• August 16 – Britain creates the colony of New Brunswick.

• September 22 – Russia establishes a colony at Kodiak, Alaska.

• November 26 – The Roman Catholic Apostolic Prefecture of the United States is established.

• December 25 – The Methodist Episcopal Church, USA is officially formed at the so-called "Christmas Conference" led by Thomas Coke and Francis Asbury.

Undated

• King Carlos III of the Spanish Empire authorizes land grants in Alta California.

• The North Carolina General Assembly incorporates the town of Morgansborough, named for Daniel Morgan. The town is designated as the county seat for Burke County, North Carolina and is subsequently renamed "Morgantown" and later shortened to become Morganton.

• The North Carolina General Assembly changes the name of Kingston, North Carolina, originally named for King George III of Great Britain, to Kinston.

• The Japanese famine continues as 300,000 die of starvation.

• Benjamin Franklin tries in vain to persuade the French to alter their clocks in winter to take advantage of the daylight.

• Benjamin Franklin invents bifocal spectacles.

• Antoine Lavoisier pioneers quantitative chemistry.

• Britain receives its first bales of imported American cotton.

• Emperor Josef II suspends the Hungarian Constitution because of a revolution in Transylvania.

• A huge locust swarm hits South Africa.

• Cholesterol is isolated.

• Carl Friedrich Gauss pioneers the field of summation with the formula summing 1:n as (n(n+1))/2, at the age of 7.

• Madame du Coudray, pioneer of modern midwifery, retires.

• The India Act requires that the governor general be chosen from outside the British East India Company and it makes company directors subject to parliamentary supervision.

Births

• January 17 – Philippe Antoine d’Ornano, Marshal of France (d. 1863)

• January 28 – George Hamilton Gordon, 4th Earl of Aberdeen, Prime Minister of the United Kingdom (d. 1860)

• February 5 – Nancy Hanks, mother of Abraham Lincoln (d. 1818)

• April 5 – Louis Spohr, German violinist and composer (d. 1859)

• April 13 – Friedrich Graf von Wrangel, Prussian field marshal (d. 1877)

• July 22 – Friedrich Bessel, German mathematician and astronomer (d. 1846)

• July 27 – Denis Davydov, Russian general and poet (d. 1839)

• October 13 – King Ferdinand VII of Spain (d. 1833)

• October 15 – Thomas Robert Bugeaud, Marshal of France and duke of Isly (d. 1849)

• October 19 – Leigh Hunt, British critic and essayist (d. 1859)

• October 19 – John McLoughlin, Canadian fur trader (d. 1857)

• October 20 – Henry Temple, 3rd Viscount Palmerston, Prime Minister of the United Kingdom (d. 1865)

• October – Sarah Biffen, English painter (d. 1850)

• November 24 – Zachary Taylor, 12th President of the United States (d. 1850)

Deaths

• January 27 – Count of St. Germain (b. 1710)

• April 26 – Nano Nagle, Irish convent founder (b. 1718)

• May 12 – Abraham Trembley, Swiss naturalist (b. 1710)

• June 13 – Henry Middleton, American president of the Continental Congress (b. 1717)

• June 26 – Caesar Rodney, American lawyer and signer of the Declaration of Independence (b. 1728)

• July 1 – Wilhelm Friedemann Bach, German composer (b. 1710)

• July 31 – Denis Diderot, French philosopher and encyclopedist (b. 1713)

• August 4 – Giovanni Battista Martini, Italian musician (b. 1706)

• August 10 – Allan Ramsay, Scottish painter (b. 1713)

• August 14 – Nathaniel Hone, Irish-born painter (b. 1718)

• August 28 – Junípero Serra, Spanish Franciscan missionary (b. 1713)

• September 4 – César-François Cassini de Thury, French astronomer (b. 1714)

• September 8 – Ann Lee, American religious leader (b. 1736)

• December 4 – Wiseman Claget, English classical scholar (b. 1721)

• December 5 – Phillis Wheatley, First African-American to publish a book (b. 1753)

• December 13 – Samuel Johnson, English writer and lexicographer (b. 1709)

• December 25 – Yosa Buson, Japanese poet and painter (b. 1716)

• December 26 – Seth Warner, American revolutionary leader (b. 1743)

• date unknown – Le Quy Don, Vietnamese philosopher, poet, encyclopedist, and government official (b. 1726)