On November 6, 2018, elections were held for 6,073 state legislative seats across 87 of the nation’s 99 state legislative chambers. Five hundred and eight elections (8.3%) resulted in control of a seat changing to a new party. Of the 508 flips, 391 (77.0%) were Republican seats that flipped to Democrats and 93 (18.2%) were Democratic seats that flipped to Republicans.
Democrats gained a net 308 seats as a result of the elections, while Republicans lost a net 294 seats. Third party and independent legislators lost a net 14 seats. Control of six state legislative chambers flipped to Democrats, including both chambers of New Hampshire’s General Court, the state senates of Colorado, Maine, and New York, and the Minnesota House of Representatives.
At least one seat changed party control in every state that held regularly-scheduled state legislative elections. New Hampshire had 77 seats flip, the most of any state. Of those, 67 were Republican-held seats that flipped to Democrats, while seven were Democratic-held seats that flipped to Republicans. Republicans flipped two seats from third party or independent legislators and Democrats flipped one. New Hampshire was followed by Maine with 26 flips and Pennsylvania with 22 flips.
Alabama, Alaska, Hawaii, and Oklahoma were the only states where Republicans had a net gain of seats. In every other state, Democrats gained more seats or the two parties gained the same number.
An additional 16 seats changed party control during special elections in 2018. Twelve were Republican seats won by Democrats while the remaining four were Democratic seats won by Republicans. Six of the Republican-held seats that flipped to Democrats in special elections flipped back to Republicans in November 2018. There was also one seat where the special election took place on the same day as the regularly-scheduled election.
Including all special elections, then, 511 seats changed party control in calendar year 2018. Democrats gained a net 309 seats while Republicans lost a net 295 seats and third party and independent legislators lost a net 14 seats.
To see a complete list of state legislative seats that changed party control in 2018 state legislative elections, click the link below.