Marcelo Soria, Brad Sutterfield, Ron Won, Mac McLeod and Craig Scott share third place at 2-under-par 68 on the South Course at Club de golf de L'ile de Montreal.
Woodard, who won the Edmonton Open two weeks ago, opened with three birdies on his first three holes. He then faltered to a double-bogey at the fourth, but came right back to birdie the fifth.
The American dropped shots at the seventh and 12th, but moved into a share of the lead with back-to-back birdies from the 14th. He parred his final three holes to remain at minus-three.
'That course is just a really good challenge of golf. There are no easy holes,' said Woodard. 'It's very demanding off the tee, and you have to keep the ball in play. There's trouble on every hole.'
Miller, son of 1973 U.S. Open champion Johnny Miller, bogeyed the first, but came back to birdie the third. He picked up three birdies between the sixth and ninth to get to 3-under.
Around the turn, he dropped another stroke at the 10th. Miller erased that error with birdies at the 12th and 16th. He faltered to another bogey at the 17th to slip back to three-under.
'I know so many of the guys out here, it feels like I'm playing college golf again,' joked Miller. 'Golf is such a small world sometimes. It seems you know everybody. Hopefully, I can get it rolling this week. All I know is if you are hitting your driver bad here, it's going to be a long day.'
Darren Griff, Paul Devenport, Jason Allred, George Bradford, Chris Wisler, Bryan Wright, Craig Matthew and Ben Pettitt share eighth place at 1-under-par.