The Nation Splits
Just before the secession of the eleven Southern states that would make up the Confederate States of America, the United States of America comprised thirty-four states and eight organized territories. Two states — Nevada and West Virginia — would be admitted to the Union during the war, and several others would be admitted shortly after. West Virginia was a particularly unexpected surprise. Though technically in the South, fifty western counties decided to break away from Virginia and remain in the Union at the onset of the war. The Union welcomed the region warmly, happy to have yet another ally.
The North and the South were decidedly different in a great many ways, but the secession of the Southern states crystallized the rift between the two regions by dividing the nation in half. A handful of slave states with at least some Union loyalties, such as Kentucky and Delaware, helped separate the North from the Deep South, but otherwise the two regions rubbed shoulders. When Virginia left the Union on April 17, 1861, it meant that Confederate forces were practically on the White House doorstep. In fact, once the war began in earnest, Lincoln could look out the windows on the second floor of the White House and see fluttering Confederate flags over Arlington Heights, Virginia, and, at night, light from Confederate campfires south of the Potomac River. As a result, the protection of the District of Columbia — the very seat of Union government — became a priority.
The Mason-Dixon Line was named for Charles Mason and Jeremiah Dixon, two British astronomers who surveyed it between 1763 and 1767. Generally composing the border between Pennsylvania and Maryland, the line today is generally regarded as the demarcation point between the Northern states and the Southern states of the Civil War.
Even after secession, neither side was particularly anxious to go to battle. Both regions had relatively small armies and neither was prepared for any type of lengthy engagement. Southern leaders said they simply wanted to be left alone, though they did identify the expansion of the borders of the Confederate States of America — perhaps in the Caribbean and Latin America — as a long-range goal. In the North, the biggest issue was the preservation of the Union, which meant bringing the Southern states back into the fold — through military force if necessary. The common thinking was that individual states may have had certain inalienable rights, but those rights did not extend to the dissolution of the Union. The future of the nation depended on putting an end to Southern secession.