November 6, 1860 Abraham Lincoln is elected
December 20, 1860 South Carolina secedes:
“We, the people of the State of South Carolina in convention assembled, do declare and ordain... that the Union now subsisting between South Carolina and other States, under the name of 'the United States of America,' is hereby dissolved.”
January 9, 1861 Mississippi secedes
January 10, 1861 Florida secedes
January 11, 1861 Alabama secedes
January 19, 1861 Georgia secedes
January 26, 1861 Louisiana secedes
January 29, 1861 Kansas admitted to Union: shifting the balance of power. Kansas is named “Bleeding Kansas” due to conflicts between pro-slavery and anti-slavery factions.
February 1, 1861 Texas secedes, despite objections of governor Sam Houston. He is replaced in March by his lieutenant governor.
February 8, 1861 Confederate States of America formed
March 2, 1861 Texas joins Confederacy
March 4, 1861 Lincoln takes office, calls secession “the essence of anarchy” and says it is his duty to “hold, occupy, and possess the property belonging to the government.”
April 12, 1861 Battle of Fort Sumter begins American Civil War. Supplies sent by Lincoln to Fort Sumter arrived too late, and the fort surrenders.
April 17, 1861 Virginia secedes
May 6, 1861 Arkansas secedes
May 7, 1861 Tennessee secedes, Virginia joins Confederacy. The Confederate capital is moved to Richmond, deemed strategically vital to the Confederacy.
May 18, 1861 Arkansas joins Confederacy
May 20, 1861 North Carolina secedes
May 21, 1861 North Carolina joins Confederacy
July 2, 1861 Tennessee joins Confederacy
August 1, 1861 Confederacy creates Arizona Territory, consisting of parts of modern day New Mexico and Arizona. It offered access to Union-controlled California.
October 31, 1861 Missouri secedes
November 20, 1861 Kentucky secedes
November 28, 1861 Missouri joins Confederacy, but never under CSA control (Confederate States of America)
December 10, 1861 Kentucky joins Confederacy, but never under CSA control
February 14, 1862 Arizona Territory organized
March 9, 1862 USS Monitor fights CSS Virginia, and the battle between the two ironclads end in a stalemate.
June 20, 1863 West Virginia splits from Virginia, admitted to Union
November 19, 1863 Lincoln delivers the Gettysburg Address:
But, in a larger sense, we can not dedicate, we can not consecrate, we can not hallow this ground. The brave men, living and dead, who struggled here, have consecrated it, far above our poor power to add or detract. The world will little note, nor long remember what we say here, but it can never forget what they did here. It is for us the living, rather, to be dedicated here to the unfinished work which they who fought here have thus far so nobly advanced. It is rather for us to be here dedicated to the great task remaining before us—that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion—that we here highly resolve that these dead shall not have died in vain—that this nation, under God, shall have a new birth of freedom—and that government of the people, by the people, for the people, shall not perish from the earth.
March 18, 1864 Ulysses S. Grant gains command of all Union armies.
October 31, 1864 Nevada admitted to USA
April 9, 1865 Confederacy surrenders, Reconstruction begins
May 5, 1866 Nevada expanded
July 24, 1866 Tennessee readmitted to Union
January 18, 1867 Nevada expanded
March 1, 1867 Nebraska admitted to USA
June 22, 1868 Arkansas readmitted to Union
June 25, 1868 Florida readmitted to Union
July 4, 1868 North Carolina and South Carolina readmitted to Union
July 9, 1868 Louisiana readmitted to Union
July 13, 1868 Alabama readmitted to Union
January 26, 1870 Virginia readmitted to Union
February 23, 1870 Mississippi readmitted to Union
March 30, 1870 Texas readmitted to Union
July 15, 1870 Georgia readmitted to Union
This visualization is originally from Thomaslegion.net.