* 1838 – Nicaragua declares independence from the Central American Federation.

* 1838 – Non-laborer slaves in most of the British Empire are emancipated.

* 1770 – William Clark, American soldier, explorer, and politician ( d. 1838 )

* 1790 – Ferenc Kölcsey, Hungarian poet and politician ( d. 1838 )

* 1838 – The Wilkes Expedition, which would explore the Puget Sound and Antarctica, weighs anchor at Hampton Roads in 1838

A close relationship developed between Hasan Ali Shah and the British, which coincided with the final years of the First Anglo-Afghan War ( 1838 – 1842 ).

* 1838 – Léon Gambetta, French statesman ( d. 1882 )

* 1838 – Paul Emile Lecoq de Boisbaudran, French scientist ( d. 1912 )

* 1915 – John Labatt, Canadian businessman and brewer ( b. 1838 )

* 1838 – John Muir, Scottish-American environmentalist ( d. 1914 )

* Aleksandra von Engelhardt ( 1754 – 1838 ), Russian lady-in-waiting

The construction commenced around the courtyard with the East Wing ( The King's Library ) in 1823 – 1828, followed by the North Wing in 1833 – 1838, which originally housed among other galleries a reading room, now the Wellcome Gallery.

* Henry Sidgwick ( 1838 – 1900 )

* Tales of Angria ( written 1838 – 1839-a collection of childhood and young adult writings including five short novels )

* 1838 – Battle of Blood River: Voortrekkers led by Andries Pretorius and Sarel Cilliers defeat Zulu impis, led by Dambuza ( Nzobo ) and Ndlela kaSompisi in what is today KwaZulu-Natal, South Africa.

* 1838 – John Labatt, Irish-Canadian brewer ( d. 1915 )

* 1806 – Jean-Olivier Chénier, Canadian physician and patriote ( d. 1838 )

* 1838 – Émile Loubet, 7th President of France ( d. 1929 )

* 1838 – Edwin Abbott Abbott, English schoolmaster, theologian, and author ( d. 1926 )

* 1881 – August Senoa, Croatian writer ( b. 1838 )

In mathematical logic, there are two quantifiers, " some " and " all ", though as Brentano ( 1838 – 1917 ) pointed out, we can make do with just one quantifier and negation.

* The Narrative of Arthur Gordon Pym of Nantucket ( 1838 ) – Poe's only complete novel

Edwin Abbott Abbott ( 20 December 1838 – 12 October 1926 ), English schoolmaster and theologian, is best known as the author of the satirical novella Flatland ( 1884 ).

1st edition, July 1838 ( John Murray, London )

Genealogical research in the United States was first systematized in the early 19th century, especially by John Farmer ( 1789 – 1838 ).

The argument and the evidence was further strengthened by Claude Pouillet in 1827 and 1838, and reasoned from experimental observations by John Tyndall in 1859, and more fully quantified by Svante Arrhenius in 1896.

Other notable pre-20th century examples include Giacomo Casanova's 1788 Icosaméron, a 5-volume, 1, 800-page story of a brother and sister who fall into the Earth and discover the subterranean utopia of the Mégamicres, a race of multicolored, hermaphroditic dwarfs ; Symzonia: A Voyage of Discovery by a " Captain Adam Seaborn " ( 1820 ) which reflected the ideas of John Cleves Symmes, Jr .; Edgar Allan Poe's 1838 novel The Narrative of Arthur Gordon Pym of Nantucket ; Jules Verne's 1864 novel A Journey to the Center of the Earth, which described a prehistoric subterranean world ; and George Sand's 1884 novel Laura, Voyage dans le Cristal where unseen and giant crystals could be found in the interior of the Earth.

John Wilkes Booth ( May 10, 1838 – April 26, 1865 ) was a famous American stage actor who assassinated President Abraham Lincoln at Ford's Theatre, in Washington, D. C., on April 14, 1865.

They purchased a farm near Bel Air in Harford County, Maryland, where John Wilkes Booth was born in a four-room log house on May 10, 1838, the ninth of ten children.

* National Gallery of Art: Selections from John James Audubon's The Birds of America ( 1826 – 1838 )

* John Brown ( Medal of Honor ) ( 1838 –?

* John Crosby Brown ( 1838 – 1909 ), partner in Brown Bros. & Co.

* John Walker ( Missouri politician ) ( 1770 – 1838 ), State Treasurer of Missouri

John Milton Hay ( October 8, 1838 – July 1, 1905 ) was an American statesman, diplomat, author, journalist, and private secretary and assistant to Abraham Lincoln.

* John McKinley – 1838

Much of Cudworth's work still remains in manuscript ; A Treatise concerning eternal and immutable Morality was published in 1731 ; and A Treatise of Freewill, edited by John Allen, in 1838 ; both are connected with the design of his magnum opus, the Intellectual System.

The United States Exploring Expedition ( 1838 – 42 ) under Charles Wilkes reached Samoa in 1839 and appointed of Englishman John C. Williams as acting U. S. consul.

* 1838 – John Ireland, American archbishop ( d. 1918 )

Traité de legislation civile et pénale was published in 1802 and then later retranslated back into English by Hildreth as The Theory of Legislation, although by this time significant portions of Dumont ’ s work had already been retranslated and incorporated into Sir John Bowring's edition of Bentham's works, which was issued in parts between 1838 and 1843.

* March 11 – John Shaw Billings, American military and medical leader ( b. 1838 )

* April 26 – John Wilkes Booth, American actor and assassin of Abraham Lincoln ( b. 1838 )

** John Grigg, New Zealand astronomer ( b. 1838 )

* October 8 – John Willis Menard, African-American politician ( b. 1838 )

** John Morley, 1st Viscount Morley of Blackburn, British politician and editor ( b. 1838 )