He finished two rounds at 12-under-par 130 and is one shot clear at Willow Creek Country Club.
Craig Lile, who shared first with Langham after the opening round, carded a 3-under 68 and is tied for second place with Edward Loar (66), Garrett Willis (64) and Richard Johnson (64) at minus-11.
Langham started on the back nine Friday and chipped his third to 3 feet to set up birdie at the par-5 10th. He missed a 12-foot par save at the long, par-3 11th, but got that stroke back with a 6-foot birdie putt at the par-5 12th.
Langham parred his next four holes then took advantage of the next par five, the 581-yard 17th. He reached the green with his three-wood second shot from 270 yards out, but two-putted for a birdie.
On his second nine, Langham rolled in a 12-foot birdie putt at the par-five first. He birdied yet another par five (there are five on the Willow Creek layout along with six par threes), the third to reach 12-under par for the championship.
He got to minus-13 with a 25-footer for birdie at the sixth, but bogeyed the par-three seventh. Langham is still in good position for his second Nationwide Tour win after titling in 1993 and 2004.
'I didn't hit it quite as good today,' acknowledged Langham. 'I hit a couple of loose shots, but still played a solid round of golf. I made a couple of bogeys, but all in all, I'm happy to be where I'm at.'
Ron Whittaker and Vance Veazey both carded rounds of 5-under 67 and are tied for sixth place at minus-10.
Mark Hensby (66), Jason Schultz (66), Tim Wilkinson (67), Chris Baryla (67), Tom Scherrer (68), Chris Anderson (67) and Jeremy Anderson (66) are tied for eighth place at 9-under 133.
The 36-hole cut fell at 4-under-par 138 and 65 players advanced to the weekend.