1861

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.
May 14 - The Canellas meteorite, an 859 gram chondrite type meteorite struck earth near Barcelona, Spain.
May 20 - American Civil War: Kentucky proclaims its neutrality which will last until September 3 when Confederate forces enter the state. North Carolina secedes from the United States
June 8 - American Civil War: Tennessee secedes from the Union.
June 9 - Lebanon separated from Syrian administration and reunited under Ottoman governor with the approval of European powers
June 15 - Benito Ju�rez formally elected president of Mexico; he temporarily stops the payments of foreign debt
June 25 - Abd-ul-Mejid, Sultan of the Ottoman Empire (1839-1861) dies and is succeeded by Abd-ul-Aziz (1861-1876).

July 1 - First issue of Vatican's newspaper L'Osservatore Romano was published.
July 2 - Ioan Kasatkin lands on Hakodate and introduces the Eastern Orthodox church into Japan.
July 21 - American Civil War: First Battle of Bull Run - At Manassas Junction, Virginia, the first major battle of the war begins (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 McClellan assumes command of the Army of the Potomac following a 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States government issues the first income tax as part of the Revenue Act of 1861 (3% of all incomes over US $800; rescinded in 1872).
August 27 - Last execution in Britain for attempted murder - Martin Doyle in Chester

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 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 - The HMS Warrior, the world's first ocean-going (all) iron-hulled armoured battleship was completed and commisioned.
October 31 - American Civil War: Citing failing health, Union General Winfield Scott resigns as Commander of the United States Army.

November 1 - American Civil War: US President Abraham Lincoln appoints George 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 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: The "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 UK and US.
November 21 - American Civil War: Confederate President Jefferson Davis appoints Judah Benjamin secretary of war.

News of Henri Mouhot's discovery of Angkor Wat published.
In Britain, the death penalty is limited to murder, embezzlement, piracy and to acts of arson perpetrated upon docks or ammunition depots.
British Empire establishes bases in Lagos to stop the slave trade.