When was the Civil War?

The American Civil War occurred in the mid-19th century.  It was a war fought between the northern Union states and the southern Confederate states.  The war was fought over a period of four years.
The Civil War began on April 12th, 1861 with the Battle of Fort Sumter.  Leading up to this battle, many southern states had succeeded from the Union.  Others followed after the battle and the start of the war.  Many people on both the Union and Confederate sides thought that the war would be a short one.  The Union had a stronger and more established army and more resources, but the Confederates fought with determination.
The Civil War raged on for years.  On April 9th, 1865, General Robert E. Lee found his army surrounded by Union troops.  He was forced to surrender at Appomattox Court House in Virginia.  News of General Lee's surrender took weeks and even months to reach other Confederate military leaders.  This was due to fragmented networks of communication.  President Johnson declared the official end of the war on May 9th, 1865.  The last Confederate general to surrender did so on June 23rd of that same year.