South Dakota Secretary of State Jason Gant predicted about 70 percent of the state's registered voters would cast ballots, down slightly from the 73 percent voter turnout in the 2008 presidential election. Gant estimated a quarter of the votes would turn out to have been cast early.
Polls will be open Tuesday from 7 a.m. to 7 p.m.
Some voters received incorrect information about polling places. South Dakota Democratic Party Chairman Ben Nesselhuf said Monday that a political action committee set up by the party sent mailings to tens of thousands of Democrats and independents, and about 5 percent listed incorrect polling places. Nesselhuf said the party was calling those voters to give them correct information.
Along with the state's lone U.S. representative, voters will chose state lawmakers and two members of the Public Utilities Commission, a three-member panel that regulates electric, natural gas and telephone utilities.
They also will decide several ballot issues, including on Republican Gov. Dennis Daugaard's plan for merit pay for teachers and proposed state constitutional amendment requiring a balanced budget.
Still, the House race has drawn the lion's share of attention this election year.
Varilek hammered Noem for missing many House committee meetings and failing to get a farm bill passed before Congress recessed for the election. He also accused her of supporting Republican plans that he said would wreck Medicare, the health care program for retirees, and give tax breaks to the wealthy.
Noem said she attended most of the meetings she was accused of skipping and missed others because she couldn't be in two meetings at once. She accused Varilek of supporting tax increases on middle-class families and small businesses and backing the health care overhaul she argued would increase costs instead of reducing them.