With all 177 state legislative districts in Illinois up for election this year, there are 354 possible primaries. Of that total, 14.4%, or 51, are contested, slightly higher than in 2018 when 45 primaries accounted for 14.3% of that year’s 314 possible primaries.
A primary is contested when more candidates file to run than there are nominations available meaning at least one candidate must lose.
The 51 contested primaries this year include 25 Democratic primaries and 26 for Republicans. For Democrats, this is down from 28 in 2020, an 11% decrease. For Republicans, that number increased 160% from 10 in 2020 to 26 in 2022.
This is also the state’s first cycle since 2014 with more Republican primaries than those for Democrats.
The difference between raw numbers and percentages of contested primaries is due to Illinois’ unique type of 2-4-4 term length system for state senators. This puts more districts up for election in 2022 compared to previous election cycles, which increases the number of possible primaries.
In Illinois, senators are divided into three groups, with each group having a two-year term at a different part of the decade between censuses, with the remainder of the decade taken up by two four-year terms.
In the election immediately following a census, all 59 Senate districts hold elections, starting a new 2-4-4 cycle. All 118 House districts are up for election each cycle.
Of the 177 districts up for election in 2022, 22 are open, meaning no incumbents filed to run. These districts are guaranteed to be won by newcomers and account for 12% of the general assembly.
Of the 155 incumbents who filed for re-election, 25—15 Democrats and 10 Republicans—face primary challengers. This is the largest number of incumbents in contested primaries since 2014.
Overall, 314 major party candidates filed to run for Illinois’ state legislative districts: 160 Democrats and 154 Republicans.
Illinois has been a Democratic trifecta since voters elected Gov. J.B. Pritzker (D) in 2018. Democrats currently hold a 40-18 majority in the Senate with one vacancy and a 73-45 majority in the House.
Illinois’ state legislative primaries are scheduled for June 28, the eighth statewide primary date of the 2022 state legislative election cycle.