De Jonge is through 36 holes at nine-under 131 and is two ahead of overnight leader Bob May, who shot a 1-under 69 and is at seven-under 133.
Jeff Gallagher fired a 5-under 65 to move into a share of third place at 6-under-par 134. He was joined there by Greg Chalmers (68), Greg Owen (68), David Hearn (66), David Schultz (69) and Garrett Osborn (66).
De Jonge began on the 10th tee and parred his first five holes. He collected his first birdie at the par-3 15th when he rolled home a 12- footer. He closed his opening side with back-to-back birdies, including a 30-footer at 17 and 15-footer at the 478-yard, closing hole.
De Jonge got his second nine going in style with a 12-foot birdie putt at one. Trouble loomed one hole later when he three-putted the par-3 second green for a bogey.
De Jonge knocked his second to the back of the green at the par-five third and got up and down for birdie. Unfortunately, history repeated itself when De Jonge bogeyed the par-three fourth.
After trading birdies and bogeys, De Jonge settled down a bit. He hit his second to 15 feet to set up birdie at the fifth, then sank a 10-footer for birdie at the sixth.
De Jonge polished off his third birdie in a row from four feet at No. 7. He appeared to be in good shape for a closing birdie at the par-five ninth, but missed a six-footer.
Despite the missed birdie opportunity at the last, De Jonge is still atop the leaderboard in his bid for a first Nationwide Tour victory.
'If I keep playing solid golf, it'll take care of itself,' said De Jonge. 'I didn't start out hitting it that good and then around the turn I got the feeling it might be a real good day.'