Both players carded bogey-free rounds, Willis with 10 birdies and Snedeker with six birdies and two eagles. They matched the Black Creek Club record established by Doug Barron in 2004.
Craig Bowden and Kevin Gessino-Kraft are tied for third place at 9-under- par 63 after a low-scoring first round that saw 128 of the 156 players shoot even-par or better.
Dicky Pride and Spike McRoy share fifth place at minus-8 -- one shot ahead of eight players who are tied for seventh.
Both leaders began their rounds on the back nine, but Willis was the first to reach 10-under after starting in an early morning group.
He opened slowly enough with four straight pars before going on a tear that saw him birdie four straight holes and 10 of his final 14.
'There are a lot of birdie holes out there, the golf course is in phenomenal shape and I don't think we've putted on greens this pure all year,' said Willis, an East Tennessee State grad.
'When you've got a lot of wedges in your hands, reachable par fives and pure greens, these guys are going to take it low.'
Low is an understatement when the scoring average is 69.538 and there are 14 players at minus-7 or better after the first round.
'I was thinking of birdieing them all,' said Willis. 'I said before the week started that it would take 30-under and I don't even know if that number is safe.'
Snedeker, a Tennessee native, opened with consecutive birdies at the 10th and 11th holes, then reached 4-under with an eagle at the par-5 14th.
Birdies at the 17th and 18th put him at minus-6 around the turn, where he would remain until going birdie-eagle at the fifth and sixth holes. Snedeker carded his final birdie at the eighth to tie Willis for the lead.
He could have led outright, if not for a missed 10-foot birdie putt at his final hole.
'I'm just disappointed I hit such a bad putt on that hole,' Snedeker lamented. 'It's not too often you get a chance to shoot that low a number. When you do you want to take advantage of it, and I hit the worst putt of the day.'
Defending champion Jason Schultz has moved on to the PGA Tour. Last year, Schultz outlasted three other players to win on the sixth playoff hole.