The 1st district includes all of St. Louis City and much of Northern St. Louis County, and it had a PVI of D+28. Incumbent Democrat Lacy Clay, who had represented the district since 2001, ran for re-election. He was re-elected with 73% of the vote in 2014.
The 2nd district includes the suburbs south and west of St. Louis City. Incumbent Republican Ann Wagner, who has represented the district since 2013, ran for re-election. She was re-elected with 64% of the vote in 2014 and the district had a PVI of R+8.
The third district stretches from exurbs of St. Louis to the state capitol Jefferson City. Incumbent Republican Blaine Luetkemeyer, who had represented the district since 2009, ran for re-election. He was re-elected with 68% of the vote in 2014. The district had a PVI of R+13.
Luetkemeyer had been speculated about as a potential candidate for Governor of Missouri in the 2016, rather than as a candidate for re-election. In January 2015, Luetkemeyer said that he would "probably" run for re-election and not run for governor.[12]
The fourth district takes in Columbia and much of rural west-central Missouri. Incumbent Republican Vicky Hartzler, who had represented the district since 2011, ran for re-election. She was re-elected in 2014 with 68% of the vote. The district had a PVI of R+13.
Jim White, a retired investment banker and 2012 State House candidate, was also running but announced on February 22, 2016, that he was suspending his campaign due to medical issues.[13][14]
The fifth district encompasses most of Jackson County, the southern part of Clay County, and three other rural counties to the east. Incumbent Democrat Emanuel Cleaver, who had represented the district since 2005, ran for re-election. He was re-elected with 51.6% of the vote in 2014. The district had a PVI of D+9.
The sixth district encompasses rural northern Missouri. Incumbent Republican Sam Graves, who had represented the district since 2001, ran for re-election. He was re-elected with 67% of the vote in 2014. The district had a PVI of R+12.
The seventh district takes in Springfield, Joplin, and much of the rest of rural southwestern Missouri. Incumbent Republican Billy Long, who had represented the district since 2011, ran for re-election. He was re-elected with 63% of the vote in 2014. The district had a PVI of R+19, the most strongly Republican district of Missouri.
Businessman Christopher Batsche previously announced a primary challenge of Senator Roy Blunt but withdrew from that race and filed to challenge Long for the Republican nomination.[21][22]
The eighth district is the most rural district of Missouri, taking in all of the rural southeastern and south-central part of the state. Incumbent Republican Jason Smith, who had represented the district since June 2013, ran for re-election. He was re-elected with 67% of the vote in 2014. The district had a PVI of R+17.