The 20-year-old Pressel, Kapaluas touring pro, was tied with Brittany Lang (71), Carin Koch (68), Jee Young Lee (70) at 5-under 211.
Pressel missed an easy opportunity to move to 6 under for the outright lead when she lipped out a 2-foot birdie putt on the final hole. She slapped herself on the rear and threw her putter onto her golf bag in disgust as she walked off the green.
Its hard to walk off the last hole like that, Pressel said. I just missed it. Nothing else to say about that.
There was a traffic jam at the top with 16 players within three shots of the lead.
Sun Young Yoo, Laura Diaz and Il Mi Chung shot 71s and were one stroke off the lead along with first-round leader Suzann Pettersen (72). Heather Young (67), Cristie Kerr (70) and Alena Sharp (72) were 3 under.
Conditions at the hilly, pine tree-lined Bay Course were windy, causing problems around the greens. However, the trades were not as strong as the two previous rounds, allowing for more birdie chances.
Pressel, who hasnt finished in the top 10 since June, surged to the top of the leaderboard after pitching in for eagle on the short par-5 15th from 45 feet and hitting a firm 7-wood tee off the tees to a foot on the 186-yard 17th.
She began the day at even par and ran into trouble in the middle of her round with bogeys on Nos. 9 and 10, but got right back on track by birdieing No. 11.
Koch, winless since the 2005 Corona Morelia Championship, birdied three of her final four holes to reach 5 under for a share of the lead.
Lang reached 5 under by tapping in for birdie on the 454-yard, par-5 15th, the easiest hole at the Bay Course. Lang bogeyed two of her first three holes.
The 23-year-old former Duke star has four top-10 finishes this year, including a fifth-place tie at Longs Drugs Challenge last week.
Lee, who has three top-10 finishes this year, birdie the final hole.
Pettersen set the pace early with two birdies in the first five holes to get to 6 under for a two-stroke lead over several players.
She seemed confident in the wind, sticking her tee shot 5 feet for birdie on the 156-yard fifth, a scenic hole which runs along the churning ocean.
Pettersen unraveled, however, starting with a three-putt bogey on the par-5 sixth where several of her shots came up short. While standing on the seventh tee box, a frustrated Petteren had a few words for her caddie.
She momentarily fell into a six-way tie for the lead at 4 under when she bogeyed the par-4 ninth but made up for it on the next hole with a nice wedge shot to about 6 feet to reach 5 under.
Pettersen, seeking her first win of the year after five in 2007, fell off the pace when she when she couldnt go up-and-down on the par-3 17th after her tee shot found the greenside bunker. She was visibly upset with her play, slamming her iron in the grass a few times on the back nine.
Annika Sorenstam, who opened with a 77, shot a 71 and was at 2 over. The 72-time LPGA winner is making one of her last competitive appearances in the United States before leaving the tour at the end of the year.
Top-ranked Lorena Ochoa was even par after a 73.
I really didnt make any putts to get some momentum going, Ochoa said. I think the grain is easy to read. Its more about the wind and some of those greens are really windy.