Charles Warren, who won the Canadian PGA Championship two weeks ago, birdied each of his last four holes for a round of 65. Warren was joined by Dave Cunningham, Jason Caron, Bryant MacKellar and Chad Collins in a tie for third at 7 under par.
Barron began his round off the 10th tee and picked up his first birdie of the day at the par-4 13th. He made it two in a row with a birdie at the 14th and got to minus-3 with a birdie at the par-5 17th.
The 35-year-old caught fire on the front side with a birdie at the first and he drained a 20-foot putt for an eagle at the par-5 second. Barron then birdied the fourth and kept the run going with a birdie at the par-5 sixth after his second shot stopped inside 15 feet.
'It was a positive round for me. I had a good attitude on the greens today,' said Barron. 'I'm just trying to keep my swing solid.'
At the par-4 ninth, Barron dropped his approach within 5 feet of the hole and rolled in the short birdie putt to secure the outright lead.
'To be honest I didn't feel real good about my game coming into this week,' said Barron, who has three top-10s and a missed cut in his last four events. 'I've lost count of how many seconds and thirds I've had out here the last few years.'
Grob ran off four birdies and a bogey over his first five holes. He collected another birdie at the seventh and made the turn at 5 under with a birdie at the ninth.
'This is a really fun place to play,' he said.
The 40-year-old, who has split time on the PGA Tour and the Nationwide Tour this season, put together a strong finish with three straight birdies starting at the 15th to post his lowest round of the year.
'I'm excited about my start,' Grob said. 'It didn't seem easy at the time, but I seem pretty refreshed right now. I saw where Doug started well, but it didn't seem like the scores were that low.'
Kyle Thompson, Keoke Cotner, Jeff Klauk, Stephen Gangluff, Lee Porter, Kelly Gibson, Brad Adamonis, Chris Zambri, John Elliott and Jon Mills share eighth place at 6-under-par 66.
Jimmy Walker, who is seeking his third victory of the season, finished six shots off the pace in a group at 3-under-par 69.