Nine state legislative elections were held across six states on March 12, 2019. Seven were general elections, and two—one in Georgia and one in Texas—were general runoff elections. Four elections were called due to the previous incumbent being elected to different positions, three were called due to appointments to different positions, and one each was called due to a resignation and a death. Democratic incumbents previously held six of the seats, and Republican incumbents previously held the other three seats.

The special elections in Mississippi all featured nonpartisan candidates, although regular Mississippi elections are partisan. Mississippi House Districts 32 and 71 were previously held by Democrats, and House District 101 was previously held by a Republican. Both seats previously held by Democrats were won outright in the general, but the District 101 race advanced to a general runoff after none of the five candidates received over 50 percent of the vote. The general runoff election is scheduled for April 2, 2019.

In Maine House District 124, Pennsylvania House Districts 114 and 190, and Texas House District 125, Democratic candidates were elected to replace their Democratic predecessors. Similarly, Republican candidates won election to seats previously held by Republican incumbents in Georgia House District 176 and Tennessee House District 32.

A state government trifecta exists when one political party simultaneously holds the governor’s office and both state legislative chambers. Maine holds a Democratic trifecta. Georgia, Mississippi, Tennessee, and Texas have Republican trifectas. Pennsylvania is under divided government.

As of March 2019, 45 state legislative special elections have been scheduled or held in 18 states. Between 2011 and 2018, an average of 77 special elections took place each year.