Jennifer Rosales, Janice Moodie and Jenna Daniels are one shot back at 5-under-par 67.
The first round was suspended due to darkness on Friday after inclement weather delayed play throughout the day.
Jackson played the back nine first and collected a birdie at the par-5 14th after her third shot stopped within 14 feet of the hole. The 23-year-old caught fire on the front side, however, and holed an 8-iron from 120 yards out for an eagle at the par-4 first.
At the par-4 third, Jackson landed her approach inside 6 feet and converted the birdie putt to reach 4 under. She faltered with a bogey at the very next hole, but played her third shot within two feet of the hole at the par-5 fifth for the first of three consecutive birdies.
'It's been a while since I've played well,' said Jackson. 'I feel like I've got some good confidence in my putter right now.'
Jackson got caught up in a bunker en route to a bogey at the par-3 eighth, but chipped in from the sand for a birdie at the par-4 ninth to cap off her round.
'I finally started hitting the ball pretty good this week,' said Jackson, a rookie on the LPGA Tour. 'I haven't really shown it in the last few weeks, but I've been hitting the ball better the last three or four weeks.'
Daniels tallied five birdies, two bogey and an eagle for her share of second. Moodie ran off five birdies for a bogey-free round.
'I really played well,' said Moodie. 'It's nice to be bogey-free.'
Rosales had to wait through the weather delay to complete her round of 67.
Meg Mallon, Lorie Kane, Angela Stanford, Karen Stupples, Wendy Ward, Dorothy Delasin, Pat Hurst, Michelle Ellis and Luciana Bemvenuti are knotted at 4-under-par 68.
Defending champion Annika Sorenstam mixed four birdies with two bogeys to finish in a group at 2-under-par 70.