10 ILCS 5/4-6
For the purpose of registering voters under this Article in addition to the method provided for precinct registration under Section 4-7, the office of the county clerk shall be open every day, except Saturday, Sunday, and legal holidays, from 9:00 a.m. to 5:00 p.m. On Saturdays the hours of registration shall be from 9:00 a.m. to 12:00 noon, and such additional hours as the county clerk may designate. If, however, the county board otherwise duly regulates and fixes the hours of opening and closing of all county offices at the county seat of any county, such regulation shall control and supersede the hours herein specified. There shall be no registration at the office of the county clerk or at the office of municipal and township or road district clerks serving as deputy registrars during the 27 days preceding any regular or special election at which the cards provided in this Article are used, or until the 2nd day following such regular or special election; provided, that if by reason of the proximity of any such elections to one another the effect of this provision would be to close registrations for all or any part of the 10 days immediately prior to such 27 day period, the county clerk shall accept, solely for use in the subsequent and not in any intervening election, registrations and transfers of registration within the period from the 27th to the 38th days, both inclusive, prior to such subsequent election. In any election called for the submission of the revision or alteration of, or the amendments to the Constitution, submitted by a Constitutional Convention, the final day for registration at the office of the election authority charged with the printing of the ballot of this election shall be the 15th day prior to the date of election.
Any qualified person residing within the county or any portion thereof subject to this Article may register or re-register with the county clerk.
Each county clerk shall appoint one or more registration or re-registration teams for the purpose of accepting the registration or re-registration of any voter who files an affidavit that he is physically unable to appear at any appointed place of registration or re-registration. Each team shall consist of one member of each political party having the highest and second highest number of registered voters in the county. The county clerk shall designate a team to visit each person with a disability and shall accept the registration or re-registration of each such person as if he had applied for registration or re-registration at the office of the county clerk.
As used in this Article, "deputy registrars" and "registration officers" mean any person authorized to accept registrations of electors under this Article.
10 ILCS 5/4-6