Election officials anticipate a low voter turnout in Arkansas.
Several Texarkana precincts had less than a dozen voters before noon on Tuesday.
Voters are deciding on the 4th Congressional District Democratic primary runoff between "Q" Byrum Hurst and Gene Jeffress.
The winner will face GOP nominee Tom Cotton in the November general election.
The Arkansas Secretary of State's office predicts a turnout of 10 percent or less in Congressional Districts one and four.
Polls were open Tuesday from 7:30 am to 7:30 p.m.