Hillary Clinton defeated Sen. Bernie Sanders (I-Vt.) in the Tennessee Democratic primary on Tuesday, according to early voting returns.

It isn't clear yet how many delegates the former secretary of state will pick up in the Volunteer State. Tennessee awards most of its 67 delegates proportionally. Clinton enjoyed a comfortable lead over Sanders in what few polls were done in the state ahead of voting.

Tennessee is one of 13 states that held its primary on Super Tuesday, when more delegates are awarded than on any other single day of the campaign season. Tennessee is one of the Southern states that make up what's known as the "SEC Primary."

The state appeared to present an uphill battle for Sanders well before ballots were cast. The self-described democratic socialist from Vermont has struggled with black voters -- he got trounced in that demographic in South Carolina -- and almost a third of Democratic voters in Tennessee in 2008 were African-American. Tennessee was considered one of the states that could make up Clinton's "Southern firewall" in the campaign.

Clinton, the Democratic front-runner, made a campaign stop in Tennessee on Sunday, speaking at a medical college in Nashville, where she was joined by the city's mayor, Megan Barry, who's endorsed her. She also stopped by a coffee shop to pose for photos with supporters.

Sanders never appeared to make a strong play for Tennessee. His campaign held a rally of its own in Nashville back in January, but it didn't include an appearance by Sanders himself. And while the Clinton campaign was airing ads in the state leading up to Super Tuesday, Tennesseans didn't see many Sanders spots hitting the airwaves.