He birdied three of his last four holes to sit atop the leaderboard. Tim Clark matched him shot for shot until the 18th hole.
Herron has four P-G-A Tour wins. He finished with a 65 and was at 12-under 198 for the tournament.
Clark is at 66 and Joe Ogilvie 69, tying them for second place, one stroke back.
Herron and Clark will be paired in tomorrow's final round.
Clark finished second last week at the John Deere Classic and second in the 2006 Masters. He's never won a P-G-A Tour event.