Editing 1788 (section)

=== April–June ===
* [[April 7]] – [[American pioneers to the Northwest Territory|American pioneers]] establish the town of [[Marietta, Ohio|Marietta]] (in modern-day [[Ohio]]), the first permanent American settlement outside the original [[Thirteen Colonies]].
* [[April 13]] – America's first recorded riot, the '[[1788 Doctors' riot|Doctors' Mob]]', begins. Residents of Manhattan are angry about grave robbers stealing bodies for doctors to dissect. The rioting is suppressed on [[April 15]].
* [[April 28]] – [[Maryland]] ratifies the [[United States Constitution]], and becomes the seventh [[U.S. state]].
* [[May 10]] – The [[Royal Dramatic Theatre]] (''Kungliga Dramatiska Teatern''), [[Sweden]]'s national drama company, is founded.
* [[May 15]] – The [[Australian frontier wars]] begin.
* [[May 23]] – [[South Carolina]] ratifies the [[United States Constitution]], and becomes the eighth [[U.S. state]].
* [[June 7]] – France: [[Day of the Tiles]], which some consider the beginning of the [[French Revolution]].
* [[June 9]] – The [[African Association]], an exploration group dedicated to plotting the [[Niger River]] and finding [[Timbuktu]], is founded in England.
* [[June 17]] – English captains [[Thomas Gilbert (sea captain)|Thomas Gilbert]] and [[John Marshall (British captain)|John Marshall]], returning from [[Botany Bay]], become the first Europeans to encounter the [[Gilbert Islands]] in the Pacific Ocean.<ref>{{cite magazine|date=1944-05-22|url=https://books.google.com/books?id=bk8EAAAAMBAJ&q=%22Thomas+Gilbert%22+captain+pacific&pg=PA91|title=The Gilberts & Marshalls: A distinguished historian recalls the past of two recently captured Pacific groups|magazine=[[Life (magazine)|Life]]|author-link=Samuel Eliot Morison|first=Samuel Eliot|last=Morison|pages=91–101|access-date=2011-12-14}}</ref> They also chart islands in "Lord Mulgrove's range", later known as the [[Marshall Islands]].
* [[June 21]] – [[New Hampshire]] ratifies the [[United States Constitution]], and becomes the ninth [[U.S. state]], enabling the Constitution to go into effect. (The latter happens on [[March 4]], [[1789]], when the first Congress elected under the new Constitution assembles.)
* [[June 25]] – The [[Virginia Ratifying Convention]] ratifies the [[United States Constitution]], and becomes the tenth [[U.S. state]] under the new government.
* [[June 26]] – [[Wolfgang Amadeus Mozart]], in [[Vienna]], completes his antepenultimate symphony, now called the ''[[Symphony No. 39 (Mozart)|Symphony No. 39]] in E-flat''.
* [[June 27]] – The [[Russo-Swedish War (1788–1790)]] breaks out following a staged attack on Swedish troops in [[Puumala]], present-day Finland.