Are you an independent student? Or dependent on your parents?
If it's the latter, you're legally a resident of whatever state they live in.
And by "dependent," I mean "did they claim you as a dependent on their taxes in 2012?"
FWIW, if you haven't been financially independent for a few years, most schools defer to your parents' stats and financial info. If you're just now making the transition to independence (e.g. getting a job after you finish undergrad), check with the specific state residency requirements.
In most states, you have to live and work (full-time) in a state for a year before you are considered "in state" for financial purposes. Each state is different. Some states (e.g. Arkansas) require 1 year of residency BEFORE you begin the app process. Some states will let you count your gap/app year as the year of qualifying residency, as long as you can show proof that you aren't there solely to apply to school (e.g. a full-time, stable job). Other states (e.g. some schools in South Carolina) will let you apply and count you as "out of state" for the 1st year of med school, but then let you claim in-state tuition.
And then, of course, there are states like CA that require 2+ years of residency.
I can't speak for IL, but OH doesn't give too big of a preference to OOS, EXCEPT for OSU, which takes ~ half the class OOS.
