(KTEN) — Oklahoma voters go to the polls on Tuesday to vote in primary runoff elections.

The marquee event will determine the candidates who will vie for the unexpired U.S. Senate seat of Republican Jim Inhofe, who plans to resign on January 3, 2023.

Rep. Markwayne Mullin (R-District 2), who won 44 percent of the vote in June's Republican primary, is facing challenger T.W. Shannon, who got the most votes among the 12 other candidates. The winner will face Democrat Kendra Horn in November's general election.

Also on Tuesday, Democratic voters will select their standard-bearer for the state's other U.S. Senate seat, held by incumbent James Lankford. Lankford will face either Jason Bollinger or Madison Horn, who are in a Democratic runoff. Horn received 37 percent of the vote in the June primary; Bollinger was in second place with 17 percent among the six candidates. Libertarian Kenneth Blevins and Independent Michael Delaney will also be on the November ballot to challenge Lankford.

Tuesday's hotly-contested GOP runoff for U.S. Congressional District 2 pits the primary's top vote-getters Avery Frix and Josh Brecheen. The winner will face Democratic candidate Naomi Andrews in November.

There are also some local races in Oklahoma communities, including a school bond election in Caddo.

Visit the Oklahoma Voter Portal to verify voter registration, view voting districts, find polling place information and to view a sample ballot.

The polls open at 7 a.m. Tuesday and will remain open until 7 p.m. Watch your vote count on KTEN News and here on KTEN.com.