1784 1785 1786 – 1787 – 1788 1789 1790
| Decades: |
1750s 1760s 1770s – 1780s – 1790s 1800s 1810s
| Centuries: |
17th century – 18th century – 19th century
1787 was a common year starting on Monday (see link for calendar).
- In Britain, Thomas Clarkson and Granville Sharpthe "Society for the Abolition of the Slave Trade" with support from John Wesley, Josiah Wedgwood and others.
- January 11 – William Herschel discovers Titania and Oberon, two moons of Uranus.
- February 4 – Shays' Rebellion fails
- May 13 – Captain Arthur Phillip leaves Portsmouth, England with eleven ships full of convicts to establish a penal colony in Australia.
- May 14 – In Philadelphia, Pennsylvania, delegates begin to meet 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 was eventually produced. George Washington presided over the Convention.
- June 6 – Franklin College, named for Benjamin Franklin, opens in Lancaster, Pennsylvania. It later merges with Marshall College to become Franklin and Marshall College.
- 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.
- August 27 – Launching a forty-five-foot craft on the Delaware River, John Fitch demonstrates the first US patent for his design.
- September 17 – United States Constitution adopted
- December 7 – Delaware ratifies the Constitution and becomes the first U.S. state.
- December 12 – Pennsylvania becomes the second U.S. state.
- December 18 – New Jersey becomes the third U.S. state.
- January 6 – Gaspard Théodore Ignace de la Fontaine, Luxembourg politician.
- March 16 – Georg Ohm, German physicist (b. 1854)
- April 26 – Ludwig Uhland, German poet (d. 1862)
- December 10 – Thomas Hopkins Gallaudet, American educator (d. 1851)