The Illinois House and Senate approved new state legislative boundaries on Aug. 31 during a special session. The maps, which passed 73-43 in the state House, and 40-17 in the state Senate, revised legislative redistricting plans enacted in June. The legislature approved maps in June in order to meet the state constitution’s June 30 deadline for approving a state legislative redistricting plan. They were adopted before the U.S. Census Bureau released block-level data from the 2020 census on Aug. 12.
Two lawsuits that were filed in federal district court challenging the June legislative maps were consolidated on July 14. The minority leaders of the Illinois House and Senate and the Mexican American Legal Defense and Educational Fund argued that those redistricting plans did not ensure that the districts had substantially equal populations because they used data from the American Community Survey (ACS) instead of the 2020 census. The trial in the consolidated lawsuit is scheduled to begin on Sept. 27.
Legislators have not yet proposed a congressional redistricting plan in Illinois.