Becky Iverson is tied with Park at 6-under-par through 15 holes, after making back-to-back birdies on 13 and 14.
Rachel Hetherington carded a 69 to share sixth place. She was joined at minus- 3 by Johanna Head, Marisa Baena, Stacy Prammanasudh, Sung Ah Yim and Jimin Kang.
Morgan Pressel, who tied for second at last year's U.S. Women's Open, finished her round at 2 under par in her 2006 debut as a professional on the LPGA Tour. Pressel reached 4-under-par after 14 holes, but three straight bogeys dropped her back to minus one, but she rebounded with a birdie on the last for 70.
The first round on the Palmer Course at Turtle Bay Resort was delayed for 50 minutes due to rain, then eventually suspended for the night due to darkness.
Park got off to a fast start as her approach to the first stopped 6 feet from the cup. She sank that birdie try, the drained an 8-footer for birdie at the second.
The 26-year-old ran home a 20-foot birdie putt on the sixth to get to 3 under. Park parred her next three holes then made a 6-foot birdie try on 10.
Park moved to minus-5 as she birdied the 16th from 4 feet. She closed with a 10-foot birdie putt on the last to end at minus-6.
'I'm looking forward to this year and I'm happy and relieved to get the first round out of the way,' said Park, a six-time winner on the LPGA Tour. 'Shooting a first score of 66, I'm very happy. I had a little butterflies in my stomach starting off the round. That is why I'm relieved.'
Hanna drained a 40-footer from the back of the green for birdie on the second. She birdied the third and fourth, both from inside 10 feet, to get to 3 under.
The 23-year-old dropped a shot on the fifth, but got that stroke back at the sixth. Hanna parred 11 straight before making a 3-foot birdie putt at the last.
'I putted well and made good par putts on the back nine,' Hanna said. 'I kept the ball in play.'
Turner played the back nine first and picked up her first birdie on the 12th. She left herself 20 feet for birdie on 14 and was able to make the putt.
The 49-year-old made a 10-foot birdie try on the first. Turner, the 1988 LPGA Championship winner, got up and down for birdie on the par-5 third. She faltered to a bogey at the fifth, but atoned for that error with a 6-foot birdie putt on six to share second place.
Lee birdied the third, but fell to plus-1 with bogeys on five and seven. The Korean birdied each of her next two holes to turn at minus-1. Lee ran off three consecutive birdies from the 11th to jump to 4 under. She parred her last five holes to remain there.
European Solheim Cuppers Maria Hjorth, Sophie Gustafson and Catriona Matthew each posted rounds of 2-under-par 70. They were joined there by Julieta Granada, Jill McGill and Soo Young Moon. Shi Hyun Ahn and Nicole Perrot are also at 2 under and were playing their final hole when play stopped.
Defending champion Jennifer Rosales is plus-2 after round one along with Paula Creamer.