Jackson County Circuit Clerk Joe Martin said it appears the county is on track to surpass the June 3 primary vote.
Martin said two precincts in District 4 he visited last were voting fairly heavily.
"That's good," he said. "We weren't happy with the turnout we had last time, I don't think anybody in the state could say they were happy with the turnout, but it looks like more people are voting.
"It's an important election. People should be voting."
Sen. Thad Cochran is facing challenger state Sen. Chris McDaniel in the GOP Runoff for the right to face Democrat Travis Childers in November in the U.S. Senate race.
Polls close at 7 p.m.