10 ILCS 125/10-5
In the year following each federal decennial census year, the Senate and House of Representatives shall each establish a committee, or the Senate and House of Representatives may create by joint resolution a joint committee of both chambers, to consider proposals to redistrict the Legislative Districts or Representative Districts, as applicable. After the receipt of the federal decennial census data from the federal government, each committee or joint committee must conduct at least 4 public hearings statewide to receive testimony and inform the public on the applicable existing Districts, with one hearing held in each of 4 distinct geographic regions of the State determined by the respective committee. All hearings shall be open to the public. The Chairperson of each committee or the Co-Chairpersons of a joint committee, as applicable, shall, no later than 6 days before any proposed hearing, post a notice with the Secretary of the Senate, Clerk of the House, or both, as applicable. The notice shall identify any measure and subject matter that may be considered during that hearing. The notice shall contain the day, hour, and place of the hearing.
10 ILCS 125/10-5