Question: Where does eastern time zone change to central?
Disambiguated questions and answers: question: Where in the midwest does the eastern time zone change to central?
Where in the south does eastern time zone change to central?
Where in the north does eastern time zone change to central?
answer: Midway through Kentucky and Tennessee
midway through florida
between Michigan and Wisconsin
Natural Questions answer: 49 CFR 71 (from the Wikipedia article "Eastern Time Zone")