Is there a consensus about what counties should be properly considered "Little Dixie" at the outbreak of war in 1861? I've seen listings in books, articles and websites from six to seventeen. If that's not bad enough even those listing a core six or seven don't share all of the same core counties.
R. Douglas Hurt's July '94 Missouri Historical Review article presents stats for Boone, Callaway, Clay, Cooper, Howard, Lafayette and Saline. The Missouri SCV site lists the core as: Audrain, Boone, Callaway, Howard, Monroe and Randolph.
(I realize that there were quite a few newer northern and foreign born residents so that the character was changing--perhaps more of a dichotomy in some counties.)