Polls opened at 6 a.m. in the Missouri Primary election, and will remain open through 7 p.m. 

Voters will chose nominees for several offices. Nine members of Missouri's congressional delegation — one senator and all eight members of the House — are on the ballot. The positions of governor, lieutenant governor, secretary of state, attorney general and treasurer are all being vacated by incumbents, according to the St. Louis Post-Dispatch.

A four-way race for the Republican gubernatorial nomination includes the following candidates: suburban St. Louis businessman John Brunner, former Navy SEAL officer Eric Greitens, former state House Speaker Catherine Hanaway and Lt. Governor Peter Kinder. The Associated Press says this primary is the first Republican governor's primary since 1992 to be so closely contested among so many candidates.

The St. Louis Post-Dispacth says that Democratic Attorney General Chris Koster, facing little-known opponents, has stockpiled nearly $11 million for the general election.

Winners in today's primary election will go on to the November 8 general election.