There are 83 legislative seats up for election this year in Colorado’s legislature—18 in the Senate and 65 in the House. There are 25 total contested primaries in 2024 (11 Democratic and 14 Republican) out of a possible 166. This rate of 15.1% is the highest since Ballotpedia began tracking this figure in 2010. 

The 26 Colorado legislators not running for re-election in 2024 aligned with the average for elections from 2010-2022 (25.6). The retirements this cycle were the third-most this decade behind 2022 (33) and 2018 (27).

Colorado legislators are limited to serving eight years in the Senate and eight years in the House. Four members of the House were term-limited in 2024.

Colorado has been a Democratic trifecta since 2019. Republicans held a trifecta from 1999-2000 and 2003-2004. The state was under divided government when Republicans held the Senate from 2015-2018.

Colorado’s state legislative primaries are scheduled for June 25.