Jutanugarn survived a double bogey at the par-3 17th to grab the top spot.
Cristie Kerr finished birdie-birdie to shoot a 66 at the Kingsmill Resort & Spa and was alone in second place. So Yeon Ryu and Dewi Claire Schreefel were tied for third at 67.
Inbee Park and Stacy Lewis, ranked first and second in the world, were among those sharing fourth place at 3-under 68.
Jutanugarn, 17, is playing this week on a sponsor's exemption. She has finished in the top five in all three of her tour appearances this season, including a runner-up showing in Thailand.
Michelle Wie, who has made three cuts in a row but has finished no higher than a tie for 28th this year, shot a 73 that put her in a tie for 85th place.
Swim Week Miami Beach 2014 [PHOTOS]