Elections for 18 of the 35 districts in the Colorado Senate will take place on Nov. 3, 2026.

Ahead of the general elections, Democrats have a 23-12 majority in the chamber. Democrats have controlled the state Senate since 2018. Republicans need to win at least six districts in 2026 to gain control, and Democrats need to lose no more than five to maintain their majority.

Ballotpedia assessed a moderate possibility of a Democratic supermajority forming in the Colorado General Assembly as a result of the 2026 elections. A supermajority is when one party has enough members in the state legislature to override a gubernatorial veto without any votes from members of the minority party. Neither party has had a supermajority in the state Senate at any point from 1992 to 2026.

In Colorado, a party must control two-thirds of the districts in each legislative chamber to have a supermajority. That's 24 districts in the state Senate and 44 in the Colorado House of Representatives. Democrats need to win control of at least one district to form a supermajority in the state Senate, and Republicans need to retain control of all districts to prevent a supermajority.

Both the Democratic Legislative Campaign Committee (DLCC) and the Republican State Leadership Committee (RSLC) are targeting the Colorado General Assembly in the 2026 general elections. According to a Ballotpedia analysis, Colorado is one of 30 states where both parties are targeting districts in the state legislature.

The DLCC is targeting five state Senate districts, including four Democratic-held districts and one Republican-held district. The DLCC official website states that "2026 is our opportunity to solidify Democratic power in the Colorado General Assembly so the state can continue serving as a firewall against the Trump administration."

The RSLC is targeting Colorado as one of eight states to focus on preserving its members. According to RSLC President Edith Jorge-Tuñón, "With the key understanding being not backtracking on the progress already made in these states, there are opportunities to expand GOP control where we are seeing frustrations in blue states."

Colorado is one of 16 states with a Democratic trifecta ahead of the general elections, meaning Democrats control the governorship and both legislative chambers. The state has had a Democratic trifecta since 2019. The last time the state had a Republican trifecta was in 2004.

Ballotpedia considers 12 districts to be battlegrounds. These include districts where the margin of victory (MOV) in the last general elections was within five percentage points, where a district is open, where a national organization is targeting, or where a district features a notable challenger to an incumbent. Seven of the 12 districts are open, while incumbents are running in the other five districts. To read more about these districts, click here.

Elections are happening in 2026 for 88 of the 99 state legislative chambers across the country. In total, 6,137 of the country's 7,386 state legislative seats are up for election in 2026.