The United States of America found itself a much smaller nation than it had been just six months earlier on June 8, 1861. On that date, Tennessee — the last state to secede — broke Union ranks and joined its Southern sisters. On that date, the Union consisted of only twenty-three states and eight territories, including the Indian Territory between Texas and Kansas. Generally, these states were all or mostly north of the Mason-Dixon Line, but they also included Kansas, California, and Oregon.

Even without the Southern states, the Union made up nearly three-fourths of the area of the previous United States of America. Its chances of victory in the event of war were considerable, at least on paper. According to the census of 1860, the population of the Northern states was nearly 22 million. Of that number, an estimated 4 million were men old enough to fight in combat if called. Even more impressive, the North had nearly 100,000 factories employing more than a million workers, and nearly 20,000 miles of railroad — more than the rest of the world combined — and 96 percent of the nation's railroad equipment. On the economic front, Union banks held 81 percent of the nation's bank deposits and nearly $56 million in gold. All of this strongly suggested that the South would be at a severe disadvantage should war break out. The North may have held the advantage in every conceivable way, but the Civil War was far from an easy triumph.