Lincicome, who claimed her only Major title at the 2009 Kraft Nabisco Championship, fired a three-under-par 69 at Blackwolf Run to end a marathon day level with fellow Americans Cristie Kerr and Lizette Salas.
"I was very in control of everything today, which is a nice feeling, obviously," a beaming Lincicome said after recording five birdies and two bogeys. "I knew exactly where my tee shots were going. I knew exactly where my irons were going.
"The putts, even if I read them wrong, I still kind of got back on track, and I was making them. It was one of those days where you were like, 'That was easy'."
Kerr, winner of the 2007 US Women's Open, parred her final 11 holes after recording three birdies in her first seven while LPGA rookie Salas mixed four birdies with a lone bogey as the trio took joint control of the year's third Major.
"My goal is to kind of play like this consistently for the rest of this week and we'll see where it falls," said world number eight Kerr, who has not triumphed on the LPGA Tour since her second Major victory at the 2010 LPGA Championship.
"I've been pretty inconsistent this year, but I've found that determination, that fire in my belly today. You never know when the light switch turns on, and I feel like it has."
Japan's Ai Miyazato, who clinched her ninth LPGA Tour title at the NW Arkansas Championship on Sunday, was among a group of four players one stroke off the pace after she opened with a four-birdie 70.
The in-form Miyazato played most of her round before the temperature peaked at around 98 degrees Fahrenheit (36.66 degrees Celsius) and said she had intentionally buried memories of her victory four days ago.
"Last week was just last week," the 27-year-old world number three said. "I try to forget about my winning because this week is just a completely different golf course and different conditions, too.
"I just trying to shake off everything and make a fresh start, and that's why I think I played really well today."
Asked how difficult it had been to cope with the soaring temperatures and high humidity, Miyazato replied: "I'm lucky because I played in the morning, so it wasn't too bad.
"But the last five holes it was really hard. I had the ice pack in my golf bag ... and that helped. It wasn't easy to keep really strong focus. You are just trying to stay in the present, and not really think about this heat."
Miyazato birdied four of her last nine holes to finish the opening round level with Americans Jennie Lee and 17-year-old Lexi Thompson as well as Spaniard Beatriz Recari.
Taiwan's world number one Yani Tseng, who has claimed five of the last 10 Major titles, carded a roller-coaster 74 that included four birdies, one double-bogey and a triple-bogey at the par-four 11th.
"I only had two bad holes," said Tseng, who ended the opening round level with Michelle Wie and South Korea's Ryu So-yeon, who won last year's US Women's Open in a play-off with compatriot Seo Hee-kyung.
"I hung in there, didn't give up any more shots, fought to the end and made up a couple of birdies on the back. Two over is not far back, and there is lots of golf to play in the next three days."