Illinois Democrats Draw Legislative Maps, Prepare to Draw Congressional Maps

Illinois is plowing full speed ahead into a redistricting period. After losing a Congressional district, the Democrats are on track to potentially widdle the GOP down to just 3-4 Congressional seats (from the current 5). With majorities in the state legislature, the Governorship, and a state Supreme Court majority, the Democrats look set to shore up their gains and potentially knock out some Republicans in the process.


The 2011 redistricting cycle in Illinois was overseen by the then-House Speaker Michael Madigan. Madigan, arguably the most powerful Illinois Democrat at the time, sought to redeem seats the party lost in the Republican wave the year prior. As a result, Illinois Democrats went from being down bad (11-8 in the state’s US House delegation) to having a 12-6 majority (Illinois lost a seat thanks to redistricting). Madigan’s objective in the 2011 Congressional redistricting cycle was to shore up the close 2010 districts upstate while also trying to create two Democratic districts downstate. He was partially successful in this approach; but all of the Democratic gains wound up being from the Chicago area or the driftless area, while Madigan’s plan to create two downstate districts fizzled. Flash forward to 2020 and the map has mostly held up, albeit not in the way that Madigan might have envisioned. All of Joe Biden’s wins in 2020 in Illinois’s Congressional Districts came in the Chicago area, while Trump won every single non-Chicago area district. Now, the Democrats control 13 out of the state’s 18 Congressional districts with the potential to add 1-2 in redistricting.

The State Legislative maps remained mostly similar to the 2000’s maps, though there was some rearranging in the Chicago suburbs to add more majority-minority districts. The overall nationwide suburban shift leftward took Democrats from a 64-54 majority in the House and a 35-24 majority in the Senate after 2010 to a 73-45 and 41-18 majority in the House and Senate respectively after 2020.

Congressional Maps – What Could Happen:

Most of the true blue Democratic districts in Illinois will look very similar to how they currently look, but there are a few lingering questions about IL-04.The majority-Hispanic district in Chicago could be split into two to create two majority-Hispanic districts, but that decision is up to the district’s current Congressman (Chuy Garcia). As of now, there have been no indications that he will back a map that splits his district in two. Beyond that proposed change, most Chicago districts are expected to look the same as they did after the 2011 redistricting cycle.

Redistricting takes a turn for the weird when it comes to the Chicago suburbs. Both IL-06 and IL-14 (which were drawn to be Republican vote sinks in the 2011 re-drawing) have trended hard to the left over the last decade, but are still somewhat competitive, especially IL-14. The good news for Illinois Democrats is that Lauren Underwood (IL-14) lives in Naperville, which is in the southern part of her sprawling district. The bad news is that another Congressman, Bill Foster of IL-11, also lives in the city. The most likely outcome is for Naperville to be split in two between the new Underwood and the new Foster districts. Additionally, Underwood is likely to win the solidly Democratic city of Aurora, which happens to be in Foster’s district. Pepper in more of Kane/Kendall counties and Underwood should have a reasonably safe district that would only be competitive in a 2010/1994-type wave for Republicans. To make up for population loss, Foster’s district could dip further into southern Will County, which could mean a potential redistricting battle against IL-16 Congressman Adam Kinzinger (R), who resides in southwestern Will County.

Outside of Chicagoland, there are a few opportunities for Democrats to gain/shore up districts. In the soon-to-be open IL-17, shedding some of the rural counties and incorporating more of metropolitan Rockford and Peoria population could turn this Obama-Trump district into one that was won by Biden in 2020 and Clinton in 2016, albeit by low single digits. The outstanding question (Chicagoland notwithstanding) concerns southern Illinois. An opportunity for the Democrats to gain a downstate district has slithered into the St. Louis/Champaign area. There stands a good chance that a new serpentine district will be created in order to ensure a Democratic downstate district. This spells trouble for current IL-13 Congressman Rodney Davis (R). Davis will either be drawn into the new Democratic district or thrown into a deeply conservative district against either Mike Bost (R, IL-12) or Mary Miller (R, IL-15).

State Legislative Maps

In the state legislative maps that have been signed off on (with lawsuits against them from the Illinois Republicans), Democrats have created 5 competitive Republican-leaning districts in the lower chamber that do not have an incumbent Republican in them, forcing any drawn-out incumbent who wants to stay in the chamber to move.

Overall, the maps are slightly stronger gerrymanders than the maps used in the 2010s for the Democrats. In the long-term, they should gain seats throughout the 2020s in both chambers. However, in the short-term, it’s less certain; our forecast actually shows Republicans are slightly favored to have a net gain in the State Senate, while the lower chamber net gain odds are about even.

Republicans have a decent chance at breaking the Democratic supermajority in the lower chamber, with the Democrats having just a 63% chance of keeping it intact. In the upper chamber, Democrats are in a much stronger position, with an 83% chance of keeping the supermajority.


Illinois Democrats stand a good chance at mowing Republicans down to just 3-4 Congressional seats following this year’s redistricting cycle. That reduction could offset almost all of the gains Republicans stand to make in redraws of states like Georgia or Ohio, as well as secure at least 13-14 seats for national Democrats. The legislative maps have been signed by Governor Pritzker but Republicans have filed lawsuits to try and keep them from being officially enacted, though this is pretty much a futile effort in a state like Illinois, dominated by Democrats on nearly every level. There is no set timeline for the Congressional maps.