To vote in Illinois, a citizen must be a U.S. citizen who has resided in an Illinois precinct for at least 30 days<span> prior to Election Day. To be eligible, a voter must be at least </span>18 years<span> of age by Election Day. A </span>17<span>-year old may vote in a primary if he or she will be </span>18 years old<span> at the subsequent general election.</span>