|Centuries:||18th century – 19th century – 20th century|
|Decades:||1770s 1780s 1790s – 1800s – 1810s 1820s 1830s|
|Years:||1798 1799 1800 – 1801 – 1802 1803 1804|
Year 1801 (MDCCCI) was a common year starting on Thursday (see link for calendar) of the Gregorian calendar (or a common year starting on Tuesday of the 12-day-slower Julian calendar).
Events of 1801
January - March
- January 1 - Legislative union of Great Britain and Ireland completed under the Act of Union 1800, bringing about the United Kingdom of Great Britain and Ireland.
- January 1 - Giuseppe Piazzi discovers the dwarf planet Ceres.
- January 21 - John Marshall is appointed Chief Justice of the United States.
- February 4 - William Pitt the Younger resigns as Prime Minister of the United Kingdom.
- February 16 - The Treaty of Lunéville ends the war ( Second Coalition) between France and Austria.
- February 19 - An electoral tie between Thomas Jefferson and Aaron Burr is resolved when Jefferson is elected President of the United States and Burr Vice President by the United States House of Representatives.
- February 27 - Washington, DC is placed under the jurisdiction of the U.S. Congress.
- March 6 - Thomas Jefferson succeeds John Adams as the President of the United States of America.
- March 21 - Second Battle of Abukir: a British army under Ralph Abercromby defeats the French troops.
- March 23 - The Russian Tsar Paul I is murdered. He is succeeded by his son Alexander I of Russia.
April - June
- April 2 - First Battle of Copenhagen - The British fleet under Admiral Sir Hyde Parker, along with Admiral Horatio Nelson, attack Copenhagen. Armed Neutrality of the North dissolved.
- May 10 - The pascha of Tripoli declares war on United States by having the flagpole on the consulate chopped down.
- June 7 - Portugal and Spain sign the Treaty of Badajoz. Portugal loses the city of Olivenza
- June 27 - Cairo falls to British troops.
July - September
- July 6 - Battle of Algeciras: The French fleet beats the British fleet.
- July 18 - Napoleon signs the Concordat of 1801 with the Pope.
October - December
- October 17 - Coup d'état in the Netherlands ( Batavian Republic).
- November 16 - First edition of New York Evening Post.
- The Indian March of Paul (January-March)
- Aachen is officially annexed by France.
- The first census is held in Great Britain. London is revealed to have 860,035 residents.
- First census in France.
- Joseph-Marie Jacquard developed a loom where the pattern being woven was controlled by punch cards.
- Ultraviolet radiation is discovered by Johann Wilhelm Ritter.
- French Revolutionary Wars (1792-1802)- Second Coalition/Egyptian Campaign
- Napoleonic Wars (1799-1815).
|Ab urbe condita||2554|
|British Regnal year||41 Geo. 3 – 42 Geo. 3|
|Chinese calendar|| 庚申年十一月十七日
— to —辛酉年十一月廿六日
|- Vikram Samvat||1857–1858|
|- Shaka Samvat||1723–1724|
|- Kali Yuga||4902–4903|
|- Ǹrí Ìgbò||801–802|
|Japanese calendar|| Kansei 13
|Juche calendar||N/A (before 1912)|
|Julian calendar||Gregorian minus 12 days|
|Minguo calendar||111 before ROC
|Thai solar calendar||2344|
January - June
- January 3 - Gijsbert Haan, Dutch-American religious leader (d. 1874)
- February 1 - Thomas Cole, American artist (d. 1848)
- towards February 13 - János Kardos Hungarian Slovenes evangelic priest, teacher and writer (d. 1875)
- February 21 - John Henry Newman, English Roman Catholic Cardinal (d. 1890)
- May 11 - Henri Labrouste, French architect (d. 1875)
- June 1 - Brigham Young, American religious leader and colonizer (d. 1877)
- June 4 - James Pennethorne, English architect (d. 1871)
- June 14 - Heber C. Kimball, American religious leader (d. 1868)
- June 30 - Frederic Bastiat, French philosopher (d. 1850)
July - December
- July 5 - David Farragut, American naval commander (d.1870)
- July 29 - George Bradshaw, English publisher (d. 1853)
- October 12 - Friedrich Frey-Herosé, member of the Swiss Federal Council (d. 1873)
- November 3 - Karl Baedeker, German author and publisher (d. 1859)
- November 3 - Vincenzo Bellini, Italian composer (d. 1835)
- November 10 - Vladimir Dal, Russian lexicographer (d. 1872)
- December 11 - Christian Dietrich Grabbe, German writer (d. 1836)
- date unknown
- Dai Xi, Chinese painter (d. 1860)
- Franciszek Ksawery Godebski, Polish writer
January - June
- February 7 - Daniel Chodowiecki, Polish painter (b. 1726)
- March 21 - Andrea Luchesi, Italian composer (b. 1741)
- March 23 - Tsar Paul of Russia (b. 1754)
- March 25 - Novalis, German poet (b. 1772)
- March 28 - Ralph Abercromby, British general (b. 1734)
- April 2 - Thomas Dadford Junior, British engineer
- April 7 - Noël François de Wailly, French lexicographer (b. 1724)
- May 17 - William Heberden, English physician (b. 1710)
- June 4 - Frederick Muhlenberg, first Speaker of the U.S. House of Representatives (b. 1750)
July - December
- September 19 - Johann Gottfried Koehler, German astronomer (b. 1745)
- October 3 - Philippe Henri, marquis de Ségur, Marshal of France (b. 1724)
- November 4 - William Shippen, American physician and Continental Congressman (b. 1712)
- 5 November - Motoori Norinaga, Japanese philologist and scholar (b. 1730)
- November 24 - Franz Moritz Graf von Lacy, Austrian field marshal (b. 1725)
- June 14 - Benedict Arnold,American Revolution traitor (b. 1741)