SmokyMountains.com puts out an annual map of when and where the peak fall foliage can be observed. They say the leaves in the mountains of eastern Tennessee will be near their peak by the last weekend of October, and reach their peak colors by the first weekend of November.
After that, peak colors will come in for central Kentucky, the middle Tennessee plateau, and most of southern Illinois by the weekend of November 12.
However, extreme southern Illinois and the Kentucky counties west of the lakes will probably not peak until the weekend of November 19.
Overall, the process of fall colors coming in to each region only lasts about three weeks until the foliage peaks and winter's browns and grays start to take effect.
On the Net:
Fall Foliage map