As must be noted, Virginia was actually quite hesitant to secede. A number of efforts were made to keep Virginia in the Union, with an early Secession Convention sending a delegation to Washington to try and ascertain the Lincoln administration's intentions. When Sumter was met with Lincoln's determination to meet Southern hostilities with force, Virginia's march to leave the Union picked up pace. On April 17, Virginia's Secession Convention voted to secede, with the final decision subject to a statewide referendum. With the data for this vote available on a county-wide basis, I thought I'd map it to see if any patterns emerge.
In the last post I tried to show a linkage between secession support across the South with the prevalence of slavery. For the purposes of this post, lets do the same thing. Our hypothesis would be that those parts of Virginia that had a higher prevalence of slavery would have a higher level of support for the secession referendum. Fortunately, I found a good map of Virginia that shows slavery by county that we can use: