April 12 – The Civil War begins, as General Pierre Beauregard and his Confederates open fire on Fort Sumter, in Charleston, South Carolina, armed with 50 cannons.
April 17 – Virginia formally withdraws from the Union. In the weeks that follow, Tennessee, Arkansas, and North Carolina follow suit, forming an 11 state Confederacy.
April 19 – President Abraham Lincoln issues a “Proclamation of Blockade” against Southern ports. Preventing the South from acquiring the ammunition, food, and other vital supplies they need to fight against the North.
July 4 – Lincoln, in a speech to Congress, states: “This is essentially a People’s contest. On the side of the Union, it is a struggle for maintaining in the world, that form, and substance of government, whose leading object is, to elevate the condition of men. . . . to afford all, an unfettered start, and a fair chance, in the race of life.” Congress authorizes a call for 500,000 men to fight for the Union Army.
July 21 – General Thomas J. Jackson is nicknamed “Stonewall” due to his continued resistance to Union Army attacks. The Union Army under General Irvin McDowell is defeated at Bull Run, and retreats to Washington.
July 27 – Following McDowell’s defeat, George B. McClellan is appointed as Commander of the Department of the Potomac.
September 11 – General John C. Frémont’s unauthorized military proclamation of emancipation in Missouri is revoked by President Lincoln, who also relieves him of command. He is replaced by General David Hunter.
November 1 – General-in-Chief of all Union Forces, Winfield Scott resigns, and he is replaced by George B. McClellan.
November 8 – President Lincoln narrowly avoids war with the English when he allows the release of two Confederate Officials who had been captured by the U.S. Navy on their way to England, while enforcing the blockade.