10 ILCS 5/6-59.01
Each registered voter lacking a permanent abode shall be canvassed by the board of election commissioners before each election. The canvass shall be by mail sent not later than 49 days preceding the election to the mailing address listed on the voter's registration record card. The board shall include in the mailing a postage prepaid return postcard. The voter must certify on the postcard his or her continued residence at the registration address and mail the postcard back to the board so that it is postmarked no later than the 26th day preceding the election.
If an application for registration is presented within the 49 day period preceding an election, then this Section shall not apply and the provisions of this Article with respect to the mailing of a verification of a registration notice shall be a canvass, except that such notice shall be mailed to the registrant's mailing address.
10 ILCS 5/6-59.01