Bohn, golfing well on his 37th birthday, notched six birdies and one bogey, finishing 36 holes at 12-under 132.
He finished the day four strokes ahead of Jeff Overton and Australian John Senden, who each carded a 69.
Two-time U.S. Open champion Lee Janzen and four other players were bunched together at 7-under 137, five shots off the pace.
Both Bohn and Janzen were among the players who managed to get in all 18 holes Friday, when thunderstorms interrupted play.
Bohn is looking to collect his second PGA Tour win and his first since 2005 when he took the B.C. Open.