Critics point to examples like Trumps comments in the Access Hollywood tape as a reason for women not to golf here. The road outside the club was relatively traffic-free and those in in attendance were there for the golf.
The biggest problem for the tournament has been the weather. Play will resume Friday morning with tee times Saturday delayed by 15 minutes.
Rio Games silver medalist Ko played in a group with Feng and gold medalist Park In-bee (77) in an Olympic podium threesome and bogeyed the last after hitting a wedge from the fringe rather than putting through the frog's hair. She will have to put in the most work on Friday with five holes left in the first round, plus all 18 in the second round.
Korda is at 3-under-par through 13 holes of her round.
Two-time major victor Brittany Lincicome told the Chicago Tribune last month she hoped Trump wouldn't make an appearance at the U.S. Open.
She came roaring back with two straight birdies after making the turn and a birdie at the last got her back to 1-over, after risky weather had forced a suspension in play.
First, she shirked any idea that she might not play well because of her travel schedule.
There are still 39 players who have to finish their first round, including Heck. Plus, her second round began shortly after she completed her first.
Feng closed out her round with eight straight pars, while Yang reached the turn level-par before firing five birdies on the back nine to move within one of the lead. Choi was the medalist in the qualifying site in Korea in June and has won a KLPGA event earlier this year.
Ko, 20, is without a win on the LPGA tour for almost a year.
Seon Woo Bae is at 139 and Carlota Ciganda, who got up before dawn to hit three shots to finish off a 69, is at 140, tied with So Yeon Ryu and In Gee Chun.
On Thursday, the personable 27-year-old from China revealed that her love for the food in America might be a secret to her success. Her first LPGA triumph came at the 2009 Lorena Ochoa Invitational in Mexico. She putted just 11 times on the front nine and 25 times on the day.
Former Open victor Cristie Kerr and Megan Khang were the best USA finishers, tied at 69. Wagner is in the middle of the pack of the 156-player field. Third-ranked Lexi Thompson was at 71, along with Stacy Lewis. Defending champion Brittany Lang barely made the cut at 2-over.