Decade-low number of open seats in Illinois’ state legislative primaries

Six seats in the Illinois state legislature are open, meaning no incumbents filed. This guarantees that at least 4% of the seats up for election will be represented by newcomers next year, a decade low. 

Twenty incumbents face primary challenges, representing 15% of all incumbents running for re-election. 

Of the 20 incumbents in contested primaries, 15 are Democrats and five are Republicans.

Illinois has 29 contested state legislative primaries this year, a 43% decrease from 2022 and a decade low (tied with 2014).

Of the 29 contested primaries, there are 18 for Democrats and 11 for Republicans. For Democrats, this is seven fewer than in 2022. For Republicans, the number is down 58% from 26 in 2022.

Overall, 232 major party candidates — 133 Democrats and 99 Republicans — filed to run. All 118 House and 20 of 59 Senate seats are up for election.

Illinois has had a Democratic trifecta since Democrats won control of the governorship in 2018. Democrats currently have a 78-40 majority in the House and a 40-19 majority in the Senate.

Illinois’ state legislative primaries are scheduled for March 19, the second — along with Ohio — statewide primary date of the 2024 state legislative election cycle.

Additional reading:

Illinois State Senate elections, 2024

Illinois House of Representatives elections, 2024