On January 3, 1861, just two weeks after South Carolina became the first state to secede from the Union, the state of Delaware rejects a similar proposal.

On January 9, 1861, a Union merchant ship, the Star of the West, is fired upon as it tries to deliver supplies to Fort Sumter in Charleston Harbor, South Carolina. This incident was the first time shots were exchanged between North and South, although it did not trigger the Civil War.

The Crittenden Compromise, the last chance to keep North and South united, dies in the U.S. Senate.

On January 29, 1861, Kansas is admitted to the Union as free state. It was the 34th state to join the Union. The struggle between pro- and anti-slave forces in Kansas was a major factor in the eruption of the Civil War.

In Montgomery, Alabama, delegates from South Carolina, Mississippi, Florida, Alabama, Georgia and Louisiana convene in Montgomery, Alabama to establish the Confederate States of America.

The earliest military action to be awarded a Medal of Honor is performed by Colonel Bernard J.D. Irwin, an assistant army surgeon serving in the first major U.S.-Apache conflict. Near Apache Pass, in southeastern Arizona, Irwin, an Irish-born doctor, volunteered to go to the rescue of Second Lieutenant George N. Bascom, who was trapped with 60 men of the U.S. Seventh Infantry by the Chiricahua Apaches.

On February 23, 1861, President-elect Abraham Lincoln arrives in Washington, D.C., amid secrecy and tight security. With seven states having already seceded from the Union since Lincoln’s election, the threat of civil war hung in the air.

With the region’s white population booming because of the Pike’s Peak gold rush, Congress creates the new Territory of Colorado.

On March 2, 1861, Texas becomes the seventh state to secede from the Union.

Abraham Lincoln becomes the 16th president of the United States on March 4, 1861. In his inauguration speech, Lincoln extended an olive branch to the South, but also made it clear that he intended to enforce federal laws in the states that seceded.

In Montgomery, Alabama, delegates from South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas adopt the Permanent Constitution of the Confederate States of America.

On March 20, 1861, President Abraham Lincoln’s sons, Willie and Tad, are diagnosed with the measles, adding to the president’s many troubles.

Four of the bloodiest years in American history begin when Confederate shore batteries under General Pierre G.T. Beauregard open fire on Union-held Fort Sumter in South Carolina’s Charleston Harbor on April 12, 1861. During the next 34 hours, 50 Confederate guns and mortars launched more than 4,000 rounds at the poorly supplied fort. On April 13, U.S. Major Robert Anderson surrendered the fort. Two days later, U.S. President Abraham Lincoln issued a proclamation calling for 75,000 volunteer soldiers to quell the Southern “insurrection.”

After a 33-hour bombardment by Confederate cannons, Union forces surrender Fort Sumter in South Carolina’s Charleston Harbor. The first engagement of the war ended in Rebel victory.

On April 19, 1861, the first blood of the American Civil War is shed when a secessionist mob in Baltimore attacks Massachusetts troops bound for Washington, D.C. Four soldiers and 12 rioters were killed.

Colonel Robert E. Lee resigns from the United States army two days after he was offered command of the Union army and three days after his native state, Virginia, seceded from the Union.

April 27, 1861, President Abraham Lincoln instructs General Winfield Scott to suspend habeas corpus as necessary to keep vital transport and supply lines clear in Maryland. This action kicks off a legal dispute with the Supreme Court.

On May 28, 1861, Chief Justice Roger B. Taney of Maryland issues Ex parte Merryman, challenging the authority of President Abraham Lincoln and the U.S. military to suspend the writ of habeas corpus (the legal procedure that prevents the government from holding an individual indefinitely without showing cause) in Maryland.

On July 11, 1861, Union troops under General George B. McClellan score another major victory in the struggle for western Virginia at the Battle of Rich Mountain. The Yankee success secured the region and ensured the eventual creation of West Virginia.

Special commissioner Albert Pike completes treaties with the members of the Choctaw and Chickasaw nations, giving the new Confederate States of America several allies in Indian Territory. Some members of the tribes also fought for the Confederacy.

Wild Bill Hickok begins to establish his reputation as a gunfighter after he shoots three men during a shootout in Nebraska.

On July 21, 1861, in the first major land battle of the Civil War, a large Union force under General Irvin McDowell is routed at the First Battle of Bull Run by a Confederate army under General Pierre G.T. Beauregard.

On August 5, 1861, President Lincoln imposes the first federal income tax by signing the Revenue Act. Strapped for cash with which to pursue the Civil War, Lincoln and Congress agreed to impose a 3 percent tax on annual incomes over $800.

Allan Pinkerton, head of the new secret service agency of the Federal government, places Confederate spy Rose O’Neal Greenhow under house arrest in Washington, D.C.

Confederate General Leonidas Polk commits a major political blunder by marching his troops into Columbus, Kentucky—negating Kentucky’s avowed neutrality and causing the Unionist legislature to invite the U.S. government to drive the invaders away.

President Abraham Lincoln observes a balloon demonstration near Washington, D.C. Both Confederate and Union armies experimented with using balloons to gather military intelligence in the early stages of the war, but the balloons proved to be dangerous and impractical for most situations.

On October 21, 1861, Union troops suffer a devastating defeat in the second major engagement of the Civil War. The Battle of Ball’s Bluff in Virginia produced the war’s first martyr and led to the creation of a Congressional committee to monitor the conduct of the war.

On October 24, 1861, workers of the Western Union Telegraph Company link the eastern and western telegraph networks of the nation at Salt Lake City, Utah, completing a transcontinental line that for the first time allows instantaneous communication between Washington, D.C., and San Francisco. Stephen J. Field, chief justice of California, sent the first transcontinental telegram to President Abraham Lincoln, predicting that the new communication link would help ensure the loyalty of the western states to the Union during the Civil War.

On November 1, 1861, President Abraham Lincoln names George Brinton McClellan general in chief of the Union army, replacing the aged and infirm Winfield Scott. In just six months, McClellan had gone from commander of the Ohio volunteers to the head of the Union army.

On November 6, 1861, Jefferson Davis is elected president of the Confederate States of America. He ran without opposition, and the election simply confirmed the decision that had been made by the Confederate Congress earlier in the year.

On November 7, 1861, Union forces under Ulysses S. Grant overrun a Confederate camp at the Battle of Belmont, Missouri, but are forced to flee when additional Confederate troops arrive. Although Grant claimed victory, the Union gained no ground and left the Confederates in firm control of that section of the Mississippi River.

On November 13, 1861, President Abraham Lincoln pays a late night visit to General George McClellan, who Lincoln had recently named general in chief of the Union army. The general retired to his chambers before speaking with the president.