In the November 2020 general election, 227 state legislative incumbents were defeated, the lowest number in any even-numbered year in the past decade. By party, those defeated incumbents include 165 Democrats, 52 Republicans, and 10 independents and members of a third party.

The 227 incumbents defeated marked a 29.5% decrease from the 322 defeated in 2018 and was 54.8% lower than the decade-high 502 incumbents defeated in the 2010 general election.

By party, a larger number of Democrats were defeated in the 2020 general election compared to Republicans. This was the fourth cycle since 2010 where the number of incumbent Democrats defeated exceeded that of Republicans. The number of incumbent Republicans defeated in general elections exceeded Democrats’ in the 2012 and 2018 state legislative elections.

The chart below shows the number of incumbents defeated in general elections since 2010 broken down by party affiliation.

Incumbents defeated in the general election represent one part of Ballotpedia’s calculation of total incumbent turnover, which measures the number of seats that will be held by newcomers in 2021. The other components of the calculation are incumbents defeated in primaries and incumbents who retired.

Incumbent turnover in 2020 reached a decade-low 1,247, meaning, overall, state legislatures will see the lowest number of newcomers since before 2010.

By party, incumbent turnover was 621 for Democrats and 626 for Republicans, the smallest gap between the two parties over the preceding decade. A greater number of Republicans were defeated in primaries than Democrats. Both Democrats and Republicans saw their lowest numbers of retirement since at least 2010 at 396 and 480, respectively.

The table below shows turnover figures from 2010 to 2020. The rightmost column shows the decade average for each metric.

For additional analyses and a full list of defeated incumbents, click here.