1864 was a leap year starting on Friday (see link for calendar).

Events

January - March

• January 21 - Maori Wars: The Tauranga Campaign starts.
• February 2 - Second war of Schleswig begins. 57.000 Austrian and Prussian troops cross Eider River to Denmark.
• February 27 - American Civil War: The first Northern prisoners arrive at the Confederate prison at Andersonville, Georgia.
• March 1- Alejandro Mon Menéndez takes office as Prime Minister of Spain
• March 10 - American Civil War: The Red River Campaign begins as Union troops reach Alexandria, Louisiana.
• March 11 - A reservoir near Sheffield bursts; 250 dead

April - June

• April 22 - The U.S. Congress passes the Coinage Act of 1864 which mandates that the inscription "In God We Trust" be placed on all coins minted as United States currency.
• May 7 - American Civil War: The Army of the Potomac, under General Ulysses S. Grant, breaks off from the Battle of the Wilderness and moves southwards.
• May 11 - American Civil War: Battle of Yellow Tavern - Confederate General JEB Stuart is mortally wounded at Yellow Tavern, Virginia .
• May 12 - American Civil War: Battle of Spotsylvania Court House: The "Bloody Angle" - thousands of Union and Confederate soldiers die.
• May 13 - American Civil War: Battle of Resaca - the battle begins with Union General Sherman fighting toward Atlanta.
• May 15 - American Civil War: Battle of New Market, Virginia - Students from the Virginia Military Institute fight alongside the Confederate Army to force Union General Franz Sigel out of the Shenandoah Valley.
• May 18 – Civil War gold hoax - New York World and the New York Journal of Commerce publish a fake proclamation that president Abraham Lincoln has issued a draft of 400.000 more soldiers
• May 20 - American Civil War: Battle of Ware Bottom Church - In the Virginia Bermuda Hundred Campaign, 10,000 troops fight in this Confederate victory
• May 26 - Montana is organized as a United States territory.
• June 5 - American Civil War: Battle of Piedmont - Union forces under General David Hunter defeat a Confederate army at Piedmont, West Virginia, taking nearly 1,000 prisoners.
• June 10 - American Civil War: Battle of Brice's Crossroads - Confederate troops under Nathan Bedford Forrest defeat a much larger Union force led by General Samuel D. Sturgis in Mississippi.
• June 12 - American Civil War: Battle of Cold Harbor: - General Ulysses S. Grant pulls his troops from their positions at Cold Harbor, Virginia and moves south.
• June 15 - Arlington National Cemetery is established when 200 acres (0.8 km²) of Arlington Mansion are officially set-aside as a military cemetery by U.S. Secretary of War Edwin M. Stanton.
• June 15 - American Civil War: Battle of Petersburg begins - Union forces under General Grant and troops led by Confederate General Robert E. Lee battle for the last time.

July - September

• July 18 - President Lincoln issues a true proclamation of conscription of 500.000 men for the US Civil War
• July 20 - American Civil War: Battle of Peachtree Creek - Near Atlanta, Georgia, Confederate forces led by General John Bell Hood unsuccessfully attack Union troops under General William T. Sherman.
• June 21 - Maori Wars: The Tauranga Campaign ends.
• July 22 - American Civil War: Battle of Atlanta - Outside of Atlanta, Georgia, Confederate General Hood leads an unsuccessful attack on Union troops under General Sherman on Bald Hill.
• July 24 - American Civil War: Battle of Kernstown - Confederate General Jubal Early defeats Union troops led by General George Crook in an effort to keep the Yankees out of the Shenandoah Valley.
• July 28 - American Civil War: Battle of Ezra Church begins - Confederate troops led by General Hood make a third unsuccessful attempt to drive Union forces under General Sherman from Atlanta, Georgia.
• July 29 - American Civil War: Confederate spy Belle Boyd is arrested by Union troops and detained at the Old Capitol Prison in Washington, DC.
• July 30 - American Civil War: Battle of the Crater - Union forces attempt to break Confederate lines by exploding a large bomb under their trenches.
• August 1 - foundation of Elgin Watch Company in Elgin, Illinois
• August 5 - American Civil War: Battle of Mobile Bay begins - At Mobile Bay near Mobile, Alabama, Admiral David Farragut leads a Union flotilla through Confederate defenses and seals one of the last major Southern ports.
• August 18 - American Civil War: Battle of Weldon Railroad - Forces under Union General Ulysses S. Grant try to cut a vital Confederate supply-line into Petersburg, Virginia, by attacking the Weldon Railroad forcing the Confederates to use wagons.
• August 22 - International Red Cross founded in Geneva, Switzerland.
• September 1 - American Civil War: Confederate General Hood evacuates Atlanta after a four month siege mounted by Union General Sherman.
• September 1 - 8 - Delegates from the Canadian colonies meet at the Charlottetown Conference to discuss Canadian Confederation.
• September 2 - American Civil War: Union forces under General Sherman enter Atlanta a day after the Confederate defenders fled the city.
• September 7 - American Civil War: Atlanta, Georgia is evacuated on orders of Union General William Tecumseh Sherman.

October - December

• October 2 - American Civil War: Battle of Saltville - Union forces attack Saltville, Virginia but are defeated by Confederate troops.
• October 5 – Cyclone kills 70.000 in Calcutta, India
• October 9 - American Civil War: Battle of Tom's Brook - Union cavalrymen in the Shenandoah Valley defeat Confederate forces at Tom's Brook, Virginia.
• October 28 - American Civil War: Second Battle of Fair Oaks ends - Union forces under General Ulysses S. Grant withdraw from Fair Oaks, Virginia , after failing to breach the Confederate defenses around Richmond, Virginia.
• October 30 - Second war of Schleswig concluded. Duke Frederick and the Danish Crown recognize Prussia's and Austria's annexation of Schleswig, Holstein and Lauenburg.
• October 30 - Helena, Montana is founded after four prospectors discover gold at "Last Chance Gulch."
• October 31 - Nevada is admitted as the 36th U.S. state
• November 4 - American Civil War: Battle of Johnsonville - At Johnsonville, Tennessee , troops under the command of Confederate General Nathan Bedford Forrest bombard a Union supply base with artillery and destroy millions of dollars in materiel.
• November 8 - U.S. presidential election, 1864: Abraham Lincoln is reelected in an overwhelming victory over George McClellan.
• November 15 - American Civil War: Sherman's March to the Sea begins - Union General Sherman burns Atlanta and starts to move south, destroying everything in his path in order to punish the Confederates for starting the war.
• November 22 - American Civil War: Sherman's March to the Sea: Confederate General John Bell Hood invades Tennessee in an unsuccessful attempt to draw Union General Sherman from Georgia.
• November 29 - Indian Wars: Sand Creek Massacre - Colorado volunteers led by Colonel John Chivington massacre at least 400 Cheyenne and Arapahoe noncombatants at Sand Creek, Colorado (where they had been given permission to camp).
• November 30 - American Civil War: Battle of Franklin - The Army of Tennessee led by General Hood mounts a dramatically unsuccessful frontal assault on Union positions around Franklin, Tennessee (Hood lost six generals and almost a third of his troops).
• December 4 - American Civil War: Sherman's March to the Sea - At Waynesboro, Georgia, forces under Union General Judson Kilpatrick prevent troops led by Confederate General Joseph Wheeler from interfering with Union General Sherman's campaign of destroying a wide swath of the South on his march to the Gulf of Mexico (Union forces did suffer more than three times the casualties as the Confederates, however).

• Imperial forces assault the Taiping capital of Nanking in the last great battle of the civil war.
• James Clerk Maxwell discovers microwaves
• First Geneva Convention
• Danevirke destroyed
• Syllabus errorum: Pope Pius IX condemns theological liberalism as an error and claims for the supremacy of RC Church authority over the civil society. He also condemns rationalism and socialism
• Russia completes its conquest of the North Caucasus, annexing Abkhazia and Circassia
• Haiti declares independence
• Brazil invades Uruguay in support of Venancio Flores . Paraguay attacks Brazil.
• John Wisden publishes first edition of Wisden Cricketer's Almanack. It goes on to become the major annual cricket publication.

Births

• January 1 - Alfred Stieglitz, photographer (d. 1946)
• January 8 - Prince Albert Victor, Duke of Clarence, second in line to the throne of the United Kingdom of Great Britain and Ireland.
• January 13 - Wilhelm Wien, German physicist (d. 1928)
• January 24 - Marguerite Durand, French actress, journalist, and feminist leader (d. 1936)
• March 13 - Alexej von Jawlensky, Russian impressionist painter (d. 1941)
• March 15 - Johan Halvorsen, Norwegian composer (d. 1935)
• March 19 - Charles Marion Russell, American artist (d. 1926)
• April 21 - Max Weber, German sociologist (d. 1920)
• May 10 - Léon Gaumont, French film pioneer (d. 1946)
• July 13 - John Jacob Astor IV, American businessman, inventor (d. 1912)
• October 25 - Alexander Gretchaninov, Russian composer (d. 1956)
• November 24 - Henri de Toulouse-Lautrec, French painter (d. 1901)
• December 6 - William S. Hart, American silent film star (d. 1946)
• Cosmo Lang, Archbishop of Canterbury (d. 1945)

Deaths

• January 13 - Stephen Foster, American composer (b. 1826)
• May 19 - Nathaniel Hawthorne, American author (b. 1804)
• June 1 - Hong Xiuquan, leader of the Taiping Rebellion (b. 1812)
• October 12 - Roger Taney, United States Supreme Court Justice (b. 1777)
• November 6 - Tuanku Imam Bonjol, Indonesian religious and military leader (b. 1772)
• December 19 - Pierre-Joseph Proudhon, French anarchist (b. 1809)
• Emil Nobel, younger brother of Alfred Nobel killed in their experiments with nitroglycerin.