The first round was suspended due to darkness with 25 players remaining on the course. That group will return to Trump National Saturday morning at 10:15 a.m. (ET).
Natalie Gulbis, Gloria Park and Jennifer Rosales are tied for fifth place at 5-under-par 66.
Defending champion Annika Sorenstam carded a 2-under 69 and is tied for 27th place.
Ward, who played for the United States in the Solheim Cup, opened with three straight birdies. She added another at the par-5 ninth to make the turn at 4-under 33.
Ward parred her first six on the back nine, then collected back-to-back birdies at 16 and 17. She parred No. 18 to get her piece of the first-round lead.
'I'm hitting the ball so well,' said Ward. 'I hit the ball well at the Solheim Cup, and was disappointed to not get a point out of it.'
Perrot recorded three birdies in her first five holes, but stumbled to a double bogey at the sixth. She managed to recover with birdies at seven and nine.
Perrot made three birdies in her first four holes on the second nine. She closed with five consecutive pars, but is in position for her first victory on the LPGA Tour.
'I played pretty good,' said Perrot, whose double bogey was the result of poor bunker play. 'I think the whole round I played very consistent and I just put the ball where I wanted to.'
Icher of France was the only one of the four co-leaders to start on the second nine. Like her fellow co-leaders, Icher flew out of the gate with four birdies in her first five holes. Her only dropped shot of the round came at the par-3 15th.
She mixed in birdies at the second, sixth and seventh holes. Icher, who won last week's Catalonia Ladies Masters on the Ladies European Tour, also has not won on the LPGA Tour.
'It's a good course,' said Icher. 'I'm really happy to play 6 under because it's a tough course. I'm going to try and keep the same routine and we'll see tomorrow.'
Han continued the trend of early starts by the leaders. She played in the afternoon tee times and recorded four birdies in her first five holes. Han added birdies at 11 and 15 to put her name in the mix.
'I'm just happy about the score,' said Han. 'I played well. Hopefully I just play like this two more days.'
Women's British Open champion Jeong Jang posted a 4-under-par 67 and is knotted in eighth place with Marcy Hart, Heather Bowie and Mi Hyun Kim. Jenna Daniels is four-under par, but has yet to complete her first round.