1861

1861 in various calendars
Gregorian calendar	1861; MDCCCLXI
Ab urbe condita	2614
Armenian calendar	1310; ԹՎ ՌՅԺ
Assyrian calendar	6611
Baháʼí calendar	17–18
Balinese saka calendar	1782–1783
Bengali calendar	1268
Berber calendar	2811
British Regnal year	24 Vict. 1 – 25 Vict. 1
Buddhist calendar	2405
Burmese calendar	1223
Byzantine calendar	7369–7370
Chinese calendar	庚申年 (Metal Monkey); 4558 or 4351; — to —; 辛酉年 (Metal Rooster); 4559 or 4352
Coptic calendar	1577–1578
Discordian calendar	3027
Ethiopian calendar	1853–1854
Hebrew calendar	5621–5622
Hindu calendars
- Vikram Samvat	1917–1918
- Shaka Samvat	1782–1783
- Kali Yuga	4961–4962
Holocene calendar	11861
Igbo calendar	861–862
Iranian calendar	1239–1240
Islamic calendar	1277–1278
Japanese calendar	Man'en 2 / Bunkyū 1; (文久元年)
Javanese calendar	1789–1790
Julian calendar	Gregorian minus 12 days
Korean calendar	4194
Minguo calendar	51 before ROC; 民前51年
Nanakshahi calendar	393
Thai solar calendar	2403–2404
Tibetan calendar	阳金猴年; (male Iron-Monkey); 1987 or 1606 or 834; — to —; 阴金鸡年; (female Iron-Rooster); 1988 or 1607 or 835

Millennium:	2nd millennium
Centuries:	18th century; 19th century ; 20th century;
Decades:	1840s; 1850s; 1860s ; 1870s; 1880s;
Years:	1858; 1859; 1860; 1861 ; 1862; 1863; 1864;

Template:C19YearInTopicX Year 1861 (MDCCCLXI) was a common year starting on Tuesday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Sunday of the 12-day slower Julian calendar).

Events of 1861

January–March

January 1 – Benito Juárez captures Mexico City.
January 2 – Friedrich Wilhelm IV of Prussia dies and is succeeded by Wilhelm I.
January 3 – American Civil War: Delaware votes not to secede from the Union.
January 9 – American Civil War: Mississippi becomes the second state to secede from the Union.
January 10 – American Civil War: Florida secedes from the Union.
January 11 – American Civil War: Alabama secedes from the Union.
January 12 – American Civil War: Major Robert Anderson sends dispatches to Washington.
January 19 – American Civil War: Georgia secedes from the Union.
January 21 – American Civil War: Jefferson Davis resigns from the United States Senate.
January 26 – American Civil War: Louisiana secedes from the Union.
January 29 – Kansas is admitted as the 34th U.S. state.
February 1 – American Civil War: Texas secedes from the Union.
February 4 – American Civil War: In Montgomery, Alabama, the Provisional Confederate Congress is formed by representatives from the first six break-away states.
February 8 – American Civil War: The Confederate States of America are formed, comprising the first six break-away States.
February 9 – American Civil War: Jefferson Davis is elected the Provisional President of the Confederate States of America by the Weed Convention at Montgomery, Alabama.
February 11 – American Civil War: The U.S. House unanimously passes a resolution guaranteeing non-interference with slavery in any state.
February 13 – Italian unification: The Siege of Gaeta, last stronghold of the Neapolitan King Francis II, is ended by Piedmontese forces. Francis goes into exile.
February 18
- American Civil War: In Montgomery, Alabama, Jefferson Davis is inaugurated as the provisional president of the Confederate States of America.
- Italian unification: Victor Emmanuel of Piedmont-Sardinia becomes King of Italy.

February 23 – President-elect Abraham Lincoln arrives secretly in Washington, D.C. after an assassination attempt in Baltimore, Maryland.
February 27 – Russian troops fire upon a crowd in Warsaw protesting Russian rule over Poland, killing 5 protesters.
February 28 – Colorado is organized as a United States territory.
March 2
- Nevada is organized as a United States territory.
- American Civil War: Texas is admitted to the Confederate States of America.
- (February 19 O.S.) – Serfdom is abolished in Imperial Russia.
March 4
- President Abraham Lincoln takes office, succeeding James Buchanan.
- American Civil War: The Stars and Bars is adopted as the flag of the Confederate States of America.
March 10 – El Hadj Umar Tall seizes the city of Segou, destroying the Bambara Empire of Mali.
March 11 – American Civil War: The Constitution of the Confederate States of America is adopted.
March 17 – Italian unification: The Kingdom of Italy is proclaimed, with Victor Emmanuel II as its king.
March 19 – The First Taranaki War ends in New Zealand.
March 20
- An earthquake completely destroys Mendoza, Argentina.
- Italian unification: The surrender of Civitella del Tronto ends the Kingdom of the Two Sicilies.
March 30 – Sir William Crookes announces his discovery of Thallium (see Discovery of the chemical elements).

April–June

April 12 – The American Civil War begins with the bombardment of Fort Sumter, South Carolina.
April 13 – American Civil War: Fort Sumter surrenders to Southern forces.
April 15 – American Civil War: President Abraham Lincoln issues a Proclamation calling for 75,000 men to confront in the South, "combinations too powerful to be suppressed in the ordinary way".
April 17 – American Civil War: The state of Virginia secedes from the Union.
April 20 – American Civil War: Robert E. Lee resigns his commission in the United States Army in order to command the forces of the state of Virginia.
April 25 – American Civil War: The Union Army arrives in Washington, D.C.
April 26 – Giovanni Schiaparelli discovers the asteroid 69 Hesperia.
April 27 – American Civil War:
- President Abraham Lincoln suspends the writ of habeas corpus in the United States.
- West Virginia secedes from Virginia.
May 6 – American Civil War: Arkansas secedes from the Union.
May 7 – American Civil War: Tennessee secedes from the Union.
May 8 – American Civil War: Richmond, Virginia is named the capital of the Confederate States of America.

May 13
- American Civil War: Victoria of the United Kingdom issues a "proclamation of neutrality" which recognizes the breakaway states as having belligerent rights.
- Comet C/1861 J1 (the "Great Comet of 1861") is discovered in Australia.
May 14 – The Canellas meteorite, an 859 gram chondrite type meteorite, strikes Earth near Barcelona, Spain.
May 20 – American Civil War: Kentucky proclaims its neutrality which lasts until September 3, when Confederate forces enter the state. North Carolina secedes from the Union.
June 9 – Lebanon is separated from Syrian administration and reunited under an Ottoman governor with the approval of the European powers.
June 15 – Benito Juárez is formally elected President of Mexico; he temporarily stops the payments of foreign debt.
June 22 – Tooley Street fire starts and takes the life of James Braidwood first director of the London Fire Brigade.
June 25 – Abd-ul-Mejid I, Sultan of the Ottoman Empire (1839–1861) dies and is succeeded by Abd-ul-Aziz (1861–1876).

July–September

July 1 – The first issue of the Vatican's newspaper L'Osservatore Romano is published.
July 1 – Taiping Rebellion: French and Imperial Chinese troops defeat Taiping forces at the Battle of Shanghai.
July 2 – Ivan Kasatkin lands on Hakodate and introduces the Eastern Orthodox Church into Japan.
July 13 – American Civil War: The Battle of Corrick's Ford takes place in western Virginia.
July 21 – American Civil War: First Battle of Bull Run: At Manassas Junction, Virginia, the first major battle of the war ends in a Confederate victory.
July 25 – American Civil War: The Crittenden-Johnson Resolution is passed by the U.S. Congress, stating that the war is being fought to preserve the Union and not to end slavery.
July 26 – American Civil War: George B. McClellan assumes command of the Army of the Potomac following the disastrous Union defeat at the First Battle of Bull Run.
August 5
- American Civil War: In order to help pay for the war effort, the United States government issues the first income tax as part of the Revenue Act of 1861 (3% of all incomes over US $800; rescinded in 1872).
- The U.S. Army abolishes flogging.
August 19 – First ascent of Weisshorn, fifth highest summit in the Alps.
August 27 – Martin Doyle's is the last execution in Britain for attempted murder.
September 3 – American Civil War: Confederate General Leonidas Polk invades neutral Kentucky, prompting the state legislature to ask for Union assistance.
September 6 – American Civil War: Forces under Union General Ulysses S. Grant bloodlessly capture Paducah, Kentucky, which gives the Union control the mouth of the Tennessee River.

October–December

October 9 – American Civil War – Battle of Santa Rosa Island: Confederate forces are defeated in their effort to take the island.
October 21 – American Civil War – Battle of Ball's Bluff: Union forces under Colonel Edward Baker are defeated by Confederate troops in the second major battle of the war. Baker, a close friend of Abraham Lincoln, is killed in the fighting.
October 24 – HMS Warrior, the world's first ocean-going (all) iron-hulled armored battleship, is completed and commissioned.
October 26- The Pony Express announces its closure.
October 28 – American Civil War: The Missouri legislature takes up a bill for Missouri's secession from the Union.
October 30 – American Civil War: The bill for Missouri's secession from the Union is passed.
October 31
- The Missouri secession bill is signed by Governor Jackson.
- American Civil War: Citing failing health, Union General Winfield Scott resigns as Commander of the United States Army.
November 1 – American Civil War: U.S. President Abraham Lincoln appoints George B. McClellan as commander of the Union Army, replacing the aged General Winfield Scott.
November 2 – American Civil War: Western Department Union General John C. Fremont is relieved of command and replaced by David Hunter.
November 6 – American Civil War: Jefferson Davis is elected president of the Confederate States of America.
November 5 – The first Melbourne Cup horse race is held in Melbourne, Victoria, Australia.
November 7 – American Civil War – Battle of Belmont: In Belmont, Missouri, Union forces led by General Ulysses S. Grant overrun a Confederate camp but are forced to retreat when Confederate reinforcements arrive.
November 8 – American Civil War – Trent Affair: The USS San Jacinto stops the United Kingdom mail ship Trent and arrests two Confederate envoys, James Mason and John Slidell, sparking a diplomatic crisis between the U.K. and U.S.
November 21 – American Civil War: Confederate President Jefferson Davis appoints Judah Benjamin Secretary of War.
November 25 – A tenement collapses in the Old Town of Edinburgh and buries 50; rescuers find 15 of them alive.
November 28 – Acting on the ordinance passed by the Jackson government, the Confederate Congress admits Missouri as the 12th Confederate state.
December 10 – American Civil War: Kentucky is accepted into the Confederate States of America.

Undated

News of Henri Mouhot's discovery of Angkor Wat is published.
In Britain, the death penalty is limited to murder, high treason, espionage, piracy with violence and acts of arson perpetrated upon docks or ammunition depots.
The British Empire establishes bases in Lagos to stop the slave trade.
First industrial meat packing plant in Uruguay established at Fray Bentos.