Paula Creamer, Joo Mi Kim and Gloria Park each carded rounds of even-par 71. They share second place at minus-5. Heather Bowie posted a two-under 69 to move into a tie for fifth at 4-under-par 209 alongside Siew-Ai Lim, who shot a 70 on Saturday.
Christina Kim tripped to a bogey at the par-3 fourth to slide back to minus-4, but she came right back with a birdie on the par-4 fifth.
The 2004 Longs Drugs Challenge winner picked up another birdie on the par-4 eighth. Kim maintained her score as she parred her final 10 holes at Wykagyl Country Club.
'The conditions are tough out there, as they haven't been cutting the rough,' said Kim. 'Like I keep stressing, the greens are very tricky. With this course there's almost a sense that you always want to hold back because if I really rip, I could hit it five feet over the hole and have 10 feet coming back for par. I think people aren't attacking as much as they could be. That's my opinion. That's how it is with me anyway.'
Creamer, who shared the second-round lead with Gloria Park, Christina Kim and Joo Mi Kim, got off to a quick start with a birdie on the first to move two strokes clear of the field. The 18-year-old stumbled back to minus-5 with a bogey on the par-3 seventh.
The rookie bounced right back with birdies on eight and nine to get back to 7 under and the lead.
Creamer tripped to a bogey on the 12th, but atoned for that mistake with a birdie on 13. She struggled on her way in as she bogeyed the 15th and 17th to fall one shot back.
'Today was probably the worst day for my ball striking. I hit the ball terrible,' Creamer said. 'I never got any momentum going and whenever I did it was caused by negative energy. A bogey, it's energy. That pumped me up. It wasn't there today, but I think I got all the bad shots out for tomorrow.'
Park had an unusual front nine. She managed seven pars, but stumbled to a double bogey on the par-3 fourth. The 2002 champion here bounced back with an eagle on the par-4 sixth as she holed her second shot to get back to 5 under.
Around the turn, Park converted back-to-back birdies from the 10th to join the leaders at 7 under. She fell back with bogeys on 14 and 15 to share second place.
'It was a very tough day,' said Park. 'There's not many birdies out there today. That's why I was a little disappointed about today. I had an eagle and then two great birdies, and then I had a mistake on 14 and 15. I made bogey on those holes, so that was my mistake for the day. Other than that, I'm pretty happy with the way I played the other holes.'
Joo Mi Kim faltered to a bogey on the second. She made up for that mistake with a birdie on three and another on six to get to 6 under.
The 20-year-old dropped shots at seven and 12. Kim got one stroke back with a birdie on 13, but dropped another shot at 15. The Korean birdied the 18th for the third straight day to share second place.
Mi Hyun Kim and Michele Redman share seventh place at 3-under-par 210. Jeong Jang and Grace Park are one stroke further back at minus-1. Hee-Won Han stands alone in 11th place at even-par 213.