The third round at the Baltusrol Golf Club saw her produce a two-putt birdie to finish 2-under 69.

Eyeing her first major title, she has the lead over South Korean Jenny Shin by one and Northern Ireland's Stephanie Meadow by two.

"Obviously I feel good," Maguire said.

"My game is in good shape.

"Yeah, I mean, if you had offered (being in first place through 54 holes) for me last Sunday, I would have taken it.

"My energy levels are good.

"I feel like we've executed our plan really well this week and tried not to think about it too much.

"Just one more day of doing the same thing."

Meanwhile, Shin came up with a bogey-free 66 that featured five birdies and will be hoping for a first win on the LPGA Tour since 2016.

Shin's only other LPGA victory was at the 2016 Volunteers of America Texas Shootout.

"It was exciting," said Shin.

"I've not been here in a while, so kind of freed me up a little bit.

"It was nice to see that I can do it, so good day."

Meadow is in third position after a 68 put her at 5-under 208.

Three shots behind her was Lee-Anne Pace (70) of South Africa and Ruoning Yin (69) of China.

Another stoke behind was American Lauren Coughlin (68) and world number one Jin Young Ko (69) of South Korea.