235 ILCS 5/9-19
Any 5 legal voters of any political subdivision or precinct in which an election has been held as provided for in this Act, may within 10 days after the canvass of the returns of such election and upon filing a bond for costs, contest the validity of such election by filing a verified petition in the Circuit Court for the county in which such political subdivision or precinct is situated, setting forth the grounds for the contest. Upon the filing of such petition a summons shall forthwith issue from such court addressed to the election official who conducted the election, notifying the official of the filing of such petition and directing him to appear before the court at the time named in the summons; provided, the time shall be not less than 5 nor more than 15 days after the filing of such petition. The procedure in such cases, as far as applicable, shall be the same as that provided in the general election law. Any registered voter in the political subdivision or precinct in which the election has been held may appear in person, or by counsel, in any such contest to defend or oppose the validity of the election.
235 ILCS 5/9-19