Under a new law, teenagers who will be 18 by the time of the November election may cast a ballot in the spring primary.
Rupert Borgsmiller is director of the Illinois State Board of Elections. He said Friday that 7,867 registrations came in from eligible 17-year-olds.
Registration for the March 18 primary closed Tuesday. But teenagers may still indicate their preferences through grace-period voting, which runs through March 15.
Lawmakers who pushed the initiative said it would expand participation in the electoral process.
Illinois is the 20th state to allow 17-year-olds to vote in primaries.