From 1861 through the spring of 1865, the United States was at war with itself. By the time the Civil War ended, the nation had been torn apart; there were, by current estimates, about 700,000 or possibly more, left dead by the war, whether in combat or illness. One of the ways used to calculate that death toll was by comparing the number of men who were enumerated in 1860 to the number who were counted ten years later, in the federal census of 1870. Lots more information on this census follows.