I keep reading that RFG is required everywhere and/or that all gasoline contains ethanol. Below is a link to EPA's website that has a map of areas of the US that are Federally required to have RFG gasoline. At the same site there are links for areas that voluntarily opt-in or have obtained a waiver to opt-out.
http://www.epa.gov/otaq/rfg/whereyoulive.htm
http://www.epa.gov/otaq/rfg/whereyoulive.htm
