In 2026, 15% of the state legislative incumbents running for election in Colorado will face primary contests, a record high since 2010.
In total, nine incumbents face contested primaries across the Colorado House and Senate. The average number of incumbents contested each year from 2010 to 2024 was five. Six of the contested incumbents are Democrats, and three are Republicans.
Colorado has 23 contested state legislative primaries in 2026. Twelve of the primaries are for Democrats, tying 2016 and 2018 for the most since 2010. Eleven are for Republicans, matching the average number of Republican primaries each election between 2010 and 2024.
In total, 173 major party candidates—90 Democrats and 83 Republicans—filed to run. All of the state’s 65 House seats and 17 of 35 Senate seats are up for election. Twenty-one of those seats are open, meaning no incumbents filed. The average number of open seats each election from 2010 to 2024 was 25.
Democrats have a 23-12 majority in the Senate and a 43-22 majority in the House. Colorado has had a Democratic trifecta since 2019, when Democrats gained control of the Senate. Colorado has elected a Democratic governor in every election since 2006.
Colorado's state legislative primaries are scheduled for June 30.
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