2018 Montana primary election live results

— -- Voters head to the polls Tuesday in Montana, deciding candidates for one of the state's U.S. Senate seats and for the state's at-large congressional district.

The most closely watched race will be the Republican primary for U.S. Senate to decide who will take on incumbent Democratic Senator Jon Tester. Four Republicans are vying for the chance to unseat Tester, who is one of ten Democratic senators in states Donald Trump won in the 2016 presidential election.

The Democratic primary for the state's at-large congressional district will decide who takes on GOP Rep. Greg Gianforte, who won the seat in a 2017 special election after Ryan Zinke was appointed U.S. Secretary of the Interior.

Montana election results will be refreshed automatically every 60 seconds after polls close at 10 p.m. ET. There is no need to refresh the page to see the latest data.