1818 1819 1820 - 1821 - 1822 1823 1824
| Decades: |
1790s 1800s 1810s - 1820s - 1830s 1840s 1850s
| Centuries: |
18th century - 19th century - 20th century
- February 23 - The Philadelphia College of Apothecaries founds the first pharmacy college.
- March 25 - Greece declares its independence from the Ottoman Empire, beginning the Greek War of Independence.
- July 10 - The United States takes possession of its newly-bought territory of Florida from Spain.
- July 28 - Peru declares independence from Spain.
- August 4 - Atkinson & Alexander publish the Saturday Evening Post for the first time as a weekly newspaper.
- September 15 - Guatemala, El Salvador, Honduras, Nicaragua and Costa Rica gain independence from Spain.
- September 27 - Mexico gains its independence from Spain.
- August 10 - Missouri is admitted as the 24th U.S. state.
- November 16 - American Old West: Missouri trader William Becknell arrives in Santa Fe, New Mexico and sells his merchandise for a huge profit (he immediately planned to return the following year over a route that became known as the Santa Fe Trail).
- In the first known obscenity case in the United States, a Massachusetts court outlawed the John Cleland novel, Fanny Hill . The publisher, Peter Holmes, was convicted for printing a "lewd and obscene" novel.
- January 8 - James Longstreet, Confederate General († 1904)
- February 3 - Elizabeth Blackwell, first female physician in the United States († 1910)
- February 11 - Hermann Allmers, writer († 1902)
- February 11 - Auguste Edouard Mariette, French Egyptologist who dug out the Sphinx († 1881)
- February 17 - Eliza Rosanna Gilbert, better known as Lola Montez († 1861)
- February 19 - August Schleicher, German linguist († 1868)
- March 1 - Joseph Hubert Reinkens, German Old Catholic bishop († 1896)
- April 9 - Charles-Pierre Baudelaire, French poet and writer († 1867)
- May 8 - Jean Henri Dunant, founder of the Red Cross and recipient of the Nobel Prize in peace 1901 († 1910)
- May 8 – William Henry Vanderbilt, entrepreneur († 1885)
- May 17 - Sebastian Kneipp, naturopathist († 1897)
- July 18 - Pauline Garcia-Viardot, mezzo-soprano and composer († 1910)
- August 10 - Jay Cooke, financier († 1905)
- October 13 - Rudolf Virchow, German doctor, pathologist, biologist, and politician († 1902)
- October 21 - Thomas Lyon-Bowes, the Monster of Glamis and member of the British Royal Family is born and recorded as dead.
- November 11 - Fyodor Dostoevsky, Russian writer († 1881)
- January 4 - Elizabeth Ann Seton, American saint (* 1774)
- February 23 - John Keats, British poet, dies in Rome (* 1795)
- March 13 - John Hunter - second governor of New South Wales (* 1737)
- May 5 - Napoleon I of France (* 1769)
- May 19 - Camille Jordan, French politician (* 1771)
- September 10 - Johann Dominicus Fiorillo, German painter and art historianaf:1821
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