The 23-year-old fired a five-under 67 at the Blythefield Country Club in Belmont on Thursday to share second with American Jessica Porvasnik.
They are one behind China's Yan Liu, who sank sank seven birdies on her way to her 66, with all three women chasing their maiden win on tour.
Porter has been making all the right noises with four career top-10s already, and though winless, the Sydneysider is loving life on the course.
She played the back nine first and rolled in birdies at Nos.12, 14 and 15 before her lone bogey on No.16.
Porter rebounded with birdies at both the 18th and first holes and added one more on her way in after finding 15 of 18 greens in regulation.
Her only win on the developmental Epson Tour has been in the state of Michigan in 2024.
"To be honest I just love it here," Porter said. "I mean, I had an awesome pro-am group (Wednesday) and I have some great host families, so I've spent a lot time here even in off weeks, which is awesome.
"Big fan of the lake life too, and the river life."
One of her threats for the rest of the week is compatriot Hannah Green, who lurks just three shots behind her.
The 2019 Women's PGA Championship winner has eight LPGA Tour victories to her name, including her major success, and has been in a rich vein of form this year.
With wins already in the HSBC Championship in February and Los Angeles Championship in April, Green also finished tied seventh at the Chevron Championship.
The West Australian had three birdies with her only blemish on the day coming on the par-four second.
One of the round's highlights was the ace by Julia Lopez Ramirez, her master shot leaving her at one under in a tie for 41st.
Leader Liu had a front-nine burst with four birdies and a bogey across a five-hole stretch (Nos. 4-8) before adding birdies at Nos.14, 15 and 18.
"I just very focus (on) my process today," Liu said. "Because it's very windy, a lot of thing out of my control so I just do what I can control."
Liu, 28, tied for fourth at the first major of the year, the Chevron Championship, but that was her best finish of the year.
Porvasnik, meanwhile, is No.284 in the world rankings and had made just seven starts in her second year on tour.
She put herself in contention with six birdies and a single bogey while finding 15 of 18 greens in regulation.
with Reuters
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