LPGA rookie Hee Won Han is alone in third place at 4-under par.
Scranton carded an eagle at the final hole Thursday when she roped a blind 3-wood shot within 10 feet from the hole. She holed her putt for only her second eagle of the year.
'It's just a guess kind of where you're aiming, and the bounce it gets down there,' said Scranton, who has seven top-10 finishes this season. 'It was a nice surprise to get down to the green and it was about 10 feet from the pin.'
The 64 matched Scranton's career lowest round, which she originally set in her first LPGA Tour win at the 1991 du Maurier Classic. The 64 also equaled Redman's record for lowest opening round in tournament history.
Scranton first broke into red figures with a 12-foot birdie at the fourth. She made three birdies in a row around the turn, including a 20-footer at No. 10 and a 50-footer at No. 11.
She posted her only bogey at No. 12 when she sailed her 6-iron approach over the green and failed to get up and down. Scranton added two long birdie putts before her eagle at the final hole.
'I was really solid. I hit it in the right place,' said Scranton. 'I just did a lot of the things the way I planned to. I drove it well and I hit a lot of greens.'
Scranton's career stalled in 1996 after major shoulder surgery caused her to miss the entire season and eventually forced her to change her swing.
'I had to completely rebuild my golf swing and it was tough,' said Scranton, who is currently 23rd on the money list. 'My swing is a lot different than it was when I was playing well in the early 90s. It's a lot better, but I was successful then and it worked. But I couldn't swing like that any more, I would tear my shoulder up again.'
Redman also posted a eagle on Thursday, with her's coming at the par-5 15th after she hit a 5-wood approach.
Redman closed her round with two birdies and spoke about how recent rest has been beneficial.
'I just had two weeks off and I feel tons better,' said Redman, currently 15th on the LPGA Tour money list. 'Today I hit it really good. I left some putts out there for sure, so I'm just hitting it well.'
Kris Tschetter, Wendy Ward, Mi Hyun Kim, Laura Diaz, Jenny Park-Choi and Betsy King are knotted at 3-under 68. Defending champion Annika Sorenstam posted a 1-over 72 and is tied for 43rd.
Full-field scores from the Sybase Big Apple Classic