A lot of folks migrated from TN, KY into IL from 1820's or earlier and it appears to me that my ancestors did so to find better farm land to support their large families. Some eventually continued west or southwest. I have IL ancestors whose descendants can be found in IA, KS, MO, TX, OK and even the Dakotas. I am not an expert, but when I first saw these migration patterns I looked in the library for general history or non-fiction books for the time period I needed. Those books are a lot more interesting than when I was in school. Hope this helps. S.Zorn