Whenever I look at US Civil War history it appears like Confederacy was one solid block of South and Union was complately from North. Was it like tht or were there individuals/communities who fought for North/South vice versa despite their ancestral origins do not belong there ? Were there any white abolishment supporters in South for example or any Southerners who fought at Union army ?
It would also be far easier for Union supporters to come out in places the Union retook primarily Tennessee where the Union took back control of the region relatively quickly(after this they began deferring to the Anaconda plan more strictly and focused on working there way down the Mississippi and capturing major coastal cities like New Orleans). This military government was naturally going to be staffed preferably by people who didn't want the state(or city in the case of places like New Orleans)to secede. In Tennessee, Virginia, Arkansas and North Carolina they'd be more of these sort of people(as per the George Thomas example Triceratops cites above) because these states didn't join the CSA due to Lincoln's election but due to the impending war and not being willing to fight the seceding states, so naturally in the upper south and border states(much of which had supported pro compromise Bell and Douglas versus pro slavery Breckenridge in the 1860 election) it would be seen considerably more and feeling were a lot more divided than in the places willing to secede over the election.