Later, of course, Daniel Decatur Emmett wrote the famed song "Dixieland."
As an historical entity, it is properly defined as the 11 states that seceded to form the Confederate States of America (SC, MS, FL, AL, GA, LA, TX, VA, AK, TN, and NC). This is the historical and traditional South.
In more modern times, Dixie's location in popular mind-set has evolved somewhat, and is usually associated with states -- or portions of them -- of the Deep South where Confederate and "Old South" pride live most strongly. As well as where the image of "moonlight and magnolias" is very rooted in reality.
Roughly, it would be an area which begins in southern Virginia and extends south into the Florida panhandle. On the northern boundary it sweeps west to take in Tennessee (and perhaps the southern parts of Kentucky),then westward thru most of Arkansas. On the southern end it runs thru the Gulf states until the northern and southern boundary lines connect to include and take in East Texas (generally, that part of the state east of Dallas).
Texas, Louisiana, Mississippi, Alabama, Arkansas, Tennessee, Georgia, North and South Carolina, Virginia and Florida. Kentucky is usually considered part of the South as well, even though it didn't secede from the union. Being a native Texan, I can tell you that the South is a great place to live if you're a normal person. I love the South.
The Governor of Missouri seceded his state before Union generals invavded and ran him out of town.
Texas, Louisiana, Mississippi, Alabama, Arkansas, Tennessee, Georgia, North and South Carolina, Virginia and Florida AND KENTUCKY.
Kentucky did seceed with the secession ordinace passing November 20, 1861. The state was admitted into the CSA December 10, 1862.