Park fired a five-under 67 to forge ahead to 12-under for the tournament, leaving her three shots clear of second-placed American Lizette Salas and a good round away from a second Major championship victory.
Salas, who started the day just a shot behind, shot a decent round of 69 but couldn't keep pace with the Korean.
The two are seemingly in a two-horse race for the title although the six players tied third at six-under will be looking to get hot on Sunday and create some pressure.
Americans Angela Stanford (66) and Jessica Korda (68), Thailand's Pornanong Phatlam (70), Frenchwoman Karine Icher (68), Norway's Suzann Pettersen (67) and seven-time Major-winning Australian Karrie Webb (67) are all six shots back.
Webb famously shot a seven-under 65 in the final round of 2006, including a hole out eagle on the last, to get into a play-off before capturing her second Kraft Nabisco championship.
Park was bogey-free in the third round showing little signs of nerves as she looks to add to her 2008 US Open title.
She has just two bogeys over the first three rounds and made multiple long-range putts on Saturday.
"I think I played really good here in the last few years but I just couldn't putt that well on these greens but this year it seems I'm reading the breaks really good and the putts are rolling in so that's been the big difference," Park said.
"I was really used to the wind after yesterday as it was the same wind from the same locations so it was a lot easier to judge today.
"I didn't hit it that close but I hit many greens and many fairways today which is what I need on this golf course."
Park was excited about the chance to take the title and take the traditional leap into Poppie's Pond adjacent to the 18th hole, a treat reserved for champions of this event.
"I feel really about my swing and my stroke at the moment and am really feeling comfortable around this golf course," she said.
"I've had a few good rounds and I just need one more tomorrow.
"Winning this one would mean a lot. It's a tournament I have always wanted to win with the special ceremony and jumping in the water.
"Everybody just wants to do that I think and it feels really special."
Salas got off to a quick start with birdies on the opening two holes lifting her into a share of the lead before Park took it back with birdie on the fifth and never relinquished it.
The American bogeyed the eighth to fall further back but gained shots on the ninth and 13th to give herself a shot at a maiden Major.
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