The American Civil War began with the secession of South Carolina on 12-17-1860. The summer before that, according to the Census Bureau, the population of the U.S. was 33,440,000, with 3,950,000 or 12% in slavery, compared with 1.5 mil in 1820. 375,000 whites owned slaves, being just under 1/4 of the white population of the South and of that, 12% owned more than 20 people, and 100 whites owned half the total number of slaves. Slaves in the Family, Edward Ball