1811

1811 in various calendars
Gregorian calendar	1811; MDCCCXI
Ab urbe condita	2564
Armenian calendar	1260; ԹՎ ՌՄԿ
Assyrian calendar	6561
Balinese saka calendar	1732–1733
Bengali calendar	1218
Berber calendar	2761
British Regnal year	51 Geo. 3 – 52 Geo. 3
Buddhist calendar	2355
Burmese calendar	1173
Byzantine calendar	7319–7320
Chinese calendar	庚午年 (Metal Horse); 4508 or 4301; — to —; 辛未年 (Metal Goat); 4509 or 4302
Coptic calendar	1527–1528
Discordian calendar	2977
Ethiopian calendar	1803–1804
Hebrew calendar	5571–5572
Hindu calendars
- Vikram Samvat	1867–1868
- Shaka Samvat	1732–1733
- Kali Yuga	4911–4912
Holocene calendar	11811
Igbo calendar	811–812
Iranian calendar	1189–1190
Islamic calendar	1225–1226
Japanese calendar	Bunka 8; (文化８年)
Javanese calendar	1737–1738
Julian calendar	Gregorian minus 12 days
Korean calendar	4144
Minguo calendar	101 before ROC; 民前101年
Nanakshahi calendar	343
Thai solar calendar	2353–2354
Tibetan calendar	阳金马年; (male Iron-Horse); 1937 or 1556 or 784; — to —; 阴金羊年; (female Iron-Goat); 1938 or 1557 or 785

Millennium:	2nd millennium
Centuries:	18th century; 19th century ; 20th century;
Decades:	1790s; 1800s; 1810s ; 1820s; 1830s;
Years:	1808; 1809; 1810; 1811 ; 1812; 1813; 1814;

1811 (MDCCCXI) was a common year starting on Tuesday of the Gregorian calendar and a common year starting on Sunday of the Julian calendar, the 1811th year of the Common Era (CE) and Anno Domini (AD) designations, the 811th year of the 2nd millennium, the 11th year of the 19th century, and the 2nd year of the 1810s decade. As of the start of 1811, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.

Events

January 8 – An unsuccessful slave revolt is led by Charles Deslondes in St. Charles and St. James, Louisiana.
January 22 – The Casas Revolt begins in San Antonio, Texas.
February 5 – British Regency: George, Prince of Wales becomes Prince Regent because of the perceived insanity of his father, King George III of the United Kingdom.
February 19 – Peninsular War: Battle of the Gebora – An outnumbered French force under Édouard Mortier routs and nearly destroys the Spanish near Badajoz in Spain.
March 1 – Citadel Massacre in Cairo: Egyptian ruler Muhammad Ali kills the last Mamluk leaders.
March 5 – Peninsular War: Battle of Barrosa, an unsuccessful French attack on a larger Anglo-Portuguese-Spanish force attempting to lift the Siege of Cádiz in Spain.
March 13 – Battle of Lissa: The British fleet defeats the French.
March 22 – The Commissioners' Plan for Manhattan is presented.
March 25 – Great Comet discovered by Honoré Flaugergues.
March 27 – Battle of Anholt: The British Navy defeats Denmark.
March 28 – Henri Christophe is proclaimed King Henri I, turning the northern State of Haiti into the Kingdom of Haiti.

April 5–6 – Revolutionary riots occur in Buenos Aires.
May 14 – Paraguay declares independence from the Spanish Empire (recognised May 15).
May 16 – Peninsular War Battle of Albuera: Spain, Portugal and Great Britain defeat the French.
May 18 – The Battle of Las Piedras is fought near Las Piedras, Banda Oriental, resulting in the first victory for the independentists of Uruguay.
June 9 – The Great Podil fire breaks out in Kiev, Ukraine.
June 15 – The Klågerup riots in Sweden.

July 5 – Venezuela declares its Independence from the Spanish Empire.
July 9 – British explorer David Thompson posts a notice at the confluence of the Columbia and Snake Rivers (in modern-day Washington (state)) claiming the area for the United Kingdom.
July 11 – The Russian Empire removes Anton II, Catholicos-Patriarch of All Georgia, from his office, placing a Russian-appointed bishop at the head of the Georgian church.
July 14
- Italian scientist Amedeo Avogadro publishes his memoire about the molecular content of gases.
- David Thompson reaches the mouth of the Columbia River, finding Fort Astoria under construction.
July 30 — Mexican War of Independence: Priest and military leader Miguel Hidalgo y Costilla is executed as a rebel by the Spanish government of New Spain.
August 3 – First ascent of Jungfrau, third highest summit in the Bernese Alps,
September – Nathan of Breslov leads the first annual Rosh Hashana kibbutz (pilgrimage) of Breslov Hasidim to the grave of Rabbi Nachman of Breslov in Uman, Ukraine.

October 11 – Inventor John Stevens' boat, the Juliana, begins operation as the first steam-powered ferry service, between New York City and Hoboken, New Jersey.
October 23 – José Gervasio Artigas and 16.000 orientales leave the Banda Oriental del Uruguay to go into exile.
October 26 – The Argentine Government declares freedom of expression for the press.
November – Luddite uprisings begin in northern England and the Midlands.
November 7 – Battle of Tippecanoe: American troops led by William Henry Harrison defeat the Native American spiritual leader Tenskwatawa, also known as The Prophet (Chief Tecumseh's brother).
November 17 – José Miguel Carrera, Chilean founding father, is sworn in as President of the executive Junta of the government of Chile.
December 2 – Reverend Samuel Marsden sends the first commercial shipment of wool from New South Wales to England.
December 16 – The New Madrid earthquake in the Mississippi Valley near New Madrid reverses the course of the river for a while. Other earthquakes along the fault occur on January 23, 1812 and February 7, 1812.
December 21 – First Constitution of Republic of Venezuela after declares its independence from Spain.