Cristie Kerr, who won the LPGA Takefuji Classic earlier this season, posted a 5-under-par 67. She shares second place with Catherine Cartwright, Liselotte Neumann, Jessica Reese and Nancy Scranton. Nine players are one stroke further back at minus-4.
Barrett's round started in fine fashion as she holed out a sand-wedge for eagle at the par-4 second. She then knocked a 5-iron within 10 feet of the cup at the sixth to setup birdie.
Barrett, who turns 38 on Saturday, then drained a 25-foot birdie putt at the ninth and came right back by sticking a 9-iron within a foot of the hole at the 10th.
She made that birdie to get to 5 under and a share of the lead. Barrett, whose lone win came at the 1989 Mitsubishi Motors Ocean State Open, sank a 10-foot birdie putt at the last to secure the overnight lead.
'I obviously got off to a good start with the eagle on No. 2,' Barrett said. 'I hit a sand-wedge in there. It was kind of funny because it was hanging on the lip, and we all got up there and it was just totally hanging. When we were walking up I thought, 'I can't believe this.' And they're saying to my caddie that he has to pull the pin, and then all of a sudden it fell in.
'Then actually one of the officials came over and was like, 'I just want to make sure about what happened on No. 2, make sure that we didn't wait long,' but we didn't because we were just walking up there. I didn't really miss a lot of greens or fairways. So it was a good day.'
Kerr knocked a sand-wedge to 6 feet to setup birdie at the 13th and came right back with a 12-foot birdie putt at the next.
The 26-year-old Kerr made a pair of 10-foot birdie putts, at 16 and 18, to head to the front side at minus-4. She again rolled home a 10-foot birdie try at the second to get to 5 under. She parred in to share second place.
'I had a lot of birdie opportunities coming in. I think the greens got a little bit quicker,' Kerr said. 'They got a little dried out as the day went on, so they got a little bit quicker.'
Scranton opened with a tap-in birdie at the first. She came up short of the third green and was unable to get up and down for par. She sank back-to-back 5-foot birdie putts from the fifth to get to minus-2.
The 43-year-old Scranton knocked an 8-iron to 5 feet to setup birdie at the eighth. Around the turn, she ran home a 7-footer for birdie at the 14th and capped her round with a birdie at the 17th to share second place.
'It's nice. Obviously, I'm not from very close to here, but it is nice to come home,' said Scranton, who hails from Centralia, Ill. 'I've got a few people coming out.'
Reese mixed three birdies and a bogey over her opening nine before carding four birdies and a bogey on the back nine.
Neumann sank five birdies on the opening nine and another birdie and a bogey on the back to share second.
Cartwright birdied four of her first seven holes from the 10th, but bogeyed the 18th. She notched birdies at the fifth and seventh to move into second.
Ashli Bunch, Christina Kim, Loraine Lambert, Jill McGill, Soo Young Moon, Grace Park, Seol An Jeon, Angela Stanford and Natalie Gulbis are the players a 4-under-par 68.
Rachel Teske, Wendy Doolan and Karrie Webb lead a group of 14 players one stroke further back at minus-3.
Two-time defending champion Annika Sorenstam posted a 1-under-par 71, where she is among a large group tied for 37th.