Support for secession was strongly correlated to the number of plantations in the region; states of the deep South which had the greatest concentration of plantations were the first to secede. The upper South slave states of Virginia, North Carolina, Arkansas, and Tennessee had fewer plantations and rejected secession until the Fort Sumter crisis forced them to choose sides. Border states had fewer plantations still and never seceded.[35][36][37]
As of 1850 the percentage of Southern whites living in families that owned slaves was 43 percent in the lower South,
36 percent in the upper South and 22 percent in the border states that fought mostly for the Union.[37]
85 percent of slaveowners who owned 100 or more slaves lived in the lower South, as opposed to one percent in the border states.[37] Ninety-five percent of blacks lived in the
South, comprising one third of the population there as opposed to one percent of the population of the North
http://en.wikipedia.org/wiki/American_Civil_War