The following excerpt on the settlement of Kentucky, the Lower Midwest and Missouri comes from Thomas C. Mackey’s article “Not a Pariah, but a Keystone: Kentucky and Secession” in Sister States, Enemy States: The Civil War In Kentucky and Tennessee:

“While geography explains why the Lincoln administration pursued different policies toward Kentucky than it did other border states like Maryland or Missouri, geography alone does not explain the significance of Kentucky in terms of secession. Ties of blood and livelihood must also be factored in. It is often overlooked that three of the four primary residents of the two White Houses of the Civil War years were Kentucky born – Abraham Lincoln, Mary Todd Lincoln, and Jefferson Davis. Furthermore, Kentucky’s ties to the rest of the nation ran east and west. From the East had come Daniel Boone and other settlers through the Cumberland Gap, and, by 1860, the largest number of non-Kentucky born residents of the state came from Virginia, not surprising as Kentucky constituted the farthest western county of Virginia until its separation and statehood in 1792. As a result of this heritage, Kentuckians looked to Virginia (and, to a lesser but notable extent, North Carolina) for political leadership even if that leadership was a love/hate relationship. The historian Russell Weigley describes Kentucky as a “self-conscious daughter of Virginia,” as indeed it was.

In addition, Kentuckians had been a restless people, populating at least the southern parts of the western states of Indiana, Illinois, and Misssouri. The distinguished historian James A. Rawley went so far as to call Missouri “the child of Kentucky” because of the 100,000 residents of that state who claimed Kentucky birth. Thus, kinship and family ties stretched from the Old Dominion to the muddy banks of the Ohio to the Missouri River and beyond.”

The whole course of secession and the outcome of the War Between the States was determined to a large extent by Kentuckians. While the Ohio River is the natural geographic border between the North and the South, Kentuckians complicated the issue by settling all over southern Indiana and southern Illinois, which is why there were so many Copperheads there.

Kentuckians colonized Missouri and Indiana. The reason that Indiana sticks out like a sore thumb in the Midwest is because it doesn’t have a metropolis like Chicago to overwhelm the Kentuckians who populated the state. During the 20th century, millions of White Southerners also took the Hillbilly Highway out of Appalachia to settle in the Great Lakes region, the cities of the Sunbelt and even in the Western states. The cultural and genetic footprint of Kentucky is much larger than the state itself because it has exported millions of its people over time.

The following excerpt comes from John Alexander Williams book Appalachia: A History:

As events unfolded, however, the productivity gains and consequent job losses came quickly, the promised benefits slowly if at all. The UMWA health and welfare fund, financed by royalties on coal output, was depleted within a few years and its commitments sharply cut back or passed along to public welfare agencies. These developments led to a “great migration from Appalachia’s mining counties and the further impoverishment of many of those who were left behind. During the 1950s, the mining counties of Kentucky, the Virginias, Tennessee, and Alabama suffered population losses between 15 percent and 30 percent; the Pennsylvania anthracite counties lost smaller percentages, mainly because they had already started exporting people during the 1930s, just under a million of them from the core; even though metropolitan areas such as Charleston, Asheville, Knoxville, and Chattanooga expanded, they failed to grow as fast as comparable areas in other parts of the country …

Thus, Kentuckians and western West Virginians moved to Ohio, Indiana and Michigan, Virginians and eastern Virginians moved to Washington-Baltimore; Georgia, Alabama, and the Carolinas absorbed more of their own Appalachian migrants than did other states, thanks to the postwar growth of such cities as Atlanta, Birmingham, Charlotte, Winston-Salem, and Greensboro.”

This excerpt comes from Richard B. Drake’s book A History of Appalachia:

“Many Appalachians solved their economic problem by migration. Hundreds of thousands did. The Appalachian “Great Migration” to the cities of the upper Midwest was already in process by 1950. The flow northward continued, and until the “Depression of 1957,” at which time the Detroit area suffered a significant economic setback, there was always a job if a mountaineer simply left his hills and struck out across the Ohio River. After 1957, the least-educated and older migrants often could not find work. Yet through the 1960s the flood continued. In all, over three million Appalachians left the region in the period from 1940 to 1970.”

3 million people left Appalachia between the 1940s and 1970s as the coal mines mechanized and laid off their workers. The North and West are full of millions of White people today who are descended from Southerners. 1 out of every 5 Californians is the descendant of an Okie.