Year 1787 (MDCCLXXXVII) was a common year starting on Monday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Friday of the 11-day slower Julian calendar).

Events of 1787

January - June

• January 6 -ommissioners to purchase 100 acres (0.40 km²) of land for the county seat of Chatham County. The town is named Pittsborough (later shortened to Pittsboro) for William Pitt the Younger.
• January 11 - William Herschel discovers Titania and Oberon, 2 moons of Uranus.

• February 4 - Shays' Rebellion fails.
• February 28 - A charter is granted establishing the institution known today as the University of Pittsburgh.
• April 2 - A Charter of Justice is signed providing the authority for the establishment of the first New South Wales (ie Australian) Courts of Criminal and Civil Jurisdiction.
• May 13 - Captain Arthur Phillip leaves Portsmouth, England with 11 ships packed with 1,000 convicts amd their jailers to establish a penal colony in Australia.
• May 14 - In Philadelphia, Pennsylvania, delegates begin arriving to write a new Constitution for the United States.
• May 25 - In Philadelphia, Pennsylvania, delegates begin to convene a Constitutional Convention intended to amend the Articles of Confederation. However, a new Constitution for the United States is eventually produced. George Washington presides over the Convention.
• May - Orangist troops attack Vreeswijk, Harmelen and Maarssen; civil war starts in the Netherlands.
• June 6 - Franklin College, named for Benjamin Franklin, opens in Lancaster, Pennsylvania. It later merges with Marshall College to become Franklin and Marshall College.
• June 20 - Oliver Ellsworth moves at the Federal Convention that the government be called the United States.
• June 28 - Princess Wilhelmina of Orange, sister of Frederick, the king of Prussia, is captured by patriots and taken to Goejanverwellesluis, and not allowed to travel to the Hague.

July - December

• July 13 - The U.S. Congress enacts the Northwest Ordinance establishing governing rules for the Northwest Territory. It also establishes procedures for the admission of new states and limits the expansion of slavery.
• July 15 - Lord's cricket ground is established and the MCC incorporated.
• August 27 - Launching a 45-foot (14 m) steam powered craft on the Delaware River, John Fitch demonstrates the first U.S. patent for his design.
• September 13 - Prussian troops enter the Netherlands. Within a few weeks 40,000 Patriots (out of a population of 2,000,000) go into exile in France (and learn from observation the ideals of the French Revolution).
• September 17 - The United States Constitution is adopted by the Constitutional Convention in Philadelphia.
• October 1 - Russo-Turkish War, 1787-1792 - Battle of Kinburn: Alexander Suvorov, though sustaining a wound, routs the Turks.
• October 27 - The first of the Federalist Papers, a series of essays calling for ratification of the U.S. Constitution, is published in a New York paper.
• October 29 - Wolfgang Amadeus Mozart's opera Don Giovanni (libretto by Lorenzo da Ponte) premieres in the Estates Theatre in Prague.
• December 7 - Delaware ratifies the Constitution and becomes the first U.S. state.
• December 8 - Mission La Purisima Concepcion is founded by Father Fermín Francisco de Lasuén, becoming the 11 mission in the California mission chain.
• December 12 - Pennsylvania becomes the second U.S. state.
• December 18 - New Jersey becomes the third U.S. state.

Undated

• In Britain, Thomas Clarkson and Granville Sharp found the Society for the Abolition of the Slave Trade with support from John Wesley, Josiah Wedgwood and others.
• The North Carolina General Assembly incorporates Waynesborough and designates it the county seat for Wayne County, North Carolina.
• The element Silicon is first identified by Antoine Lavoisier as a component of the Latin term silex or "Flints" (meaning "Hard Rocks").

Births

• February 10 - William Bradley, Britain's tallest ever man (d. 1820)
• March 7 - George Bethune English, American explorer and writer (d. 1828)
• March 11 - Ivan Nabokov, Russian General
• March 17 - Edmund Kean, British actor (d. 1833)
• April 26 - Ludwig Uhland, German poet (d. 1862)
• December 10 - Thomas Hopkins Gallaudet, American educator (d. 1851)
• December 16 - Mary Russell Mitford, English novelist and dramatist (d. 1855)

Deaths

• February 13
  • Rudjer Boscovich, Croatian scientist and diplomat (b. 1711)
  • Charles Gravier, comte de Vergennes, French statesman and diplomat (b. 1717)
• April 1 - Floyer Sydenham, English classical scholar (b. 1710)
• April 2 - Thomas Gage, British general (b. 1719)
• May 10 - William Watson, English physician and scientist (b. 1715)
• May 28 - Leopold Mozart, Austrian composer (b. 1719)
• June 20 - Carl Friedrich Abel, German composer (b. 1723)
• July 4 - Charles de Rohan, prince de Soubise, Marshal of France (b. 1715)
• August 1 - Alphonsus Liguori, Italian founder of the Redemptionist order (b. 1696)
• October 7 - Henry Muhlenberg, German-born founder of the U.S. Lutheran Church (b. 1711)
• November 3 - Robert Lowth, English bishop and grammarian (b. 1710)
• November 15 - Christoph Willibald Gluck, German composer (b. 1714)
• December 18 - Francis William Drake, British admiral and Governor of Newfoundland (b. 1724)
• December 18 - Soame Jenyns, English writer (b. 1704)