Boeljon said she used a nine iron to drop the ball in from 126 yards away on hole 16 to finish the day in a tie with Lydia Ko and Angela Stanford at 65.
"I only realized it (was in the hole) by the lady that was behind the green that put her hands up," said Boeljon, whose name is pronounced Bool'-yon.
"I thought (to myself) 'I guess it's in' because we couldn't see because of the sun. Everyone was high-fiving. I go up to the hole and see it's in. Pretty cool."
It was first ace on the LPGA tour for the 26-year-old from Alkmaar, Netherlands.
It was the crown jewel in a late charge by Boeljon that saw her birdie 15, ace 16, then birdie 17 in the sticky, dead-calm, late afternoon heat at the Royal Mayfair Golf Club.
"I'm lucky that I hit that shot into the hole," she said.
"For me it didn't feel anything different. You just try to do your thing. Go through your routine again and try to play shot by shot.
"I'm just pleased with my game at the moment."
Boeljon, in her third year on tour, is far from a household name.
She is 120th on the Rolex rankings and has yet to win a tournament. Her best finish was a tie for 15th at the Women's Australian Open in February.
Her late day magic overshadowed a hot start in the morning by Ko, the tournament's defending champion.
The 16-year-old New Zealander came out with irons blazing, birdieing four of the first seven holes, followed up by two birdies and a bogey on the back nine.
Ko said that, ironically, when she birdied the 417-yard first hole, she figured she was in for a bad day.
"When I start off with a birdie I haven't really played that well, so yeah I was kind of nervous," she said.
She added she felt a bit of pressure coming in as the one to beat.
"Because you're the defending champion, people are going to expect more," she said.
"(But) I called my dad a couple of days ago and he just said, 'Relax. You can't control everything. Just play the game that you want to play.'"
Stanford was steady from start to finish, hitting 13 of 18 greens in regulation, carding three birdies on the front nine and two on the back.
The 35-year-old from Fort Worth, Texas, is looking for her sixth LPGA win and has been playing her best golf of the season to date.
She ended up tied for 17th at the Women's British Open earlier this month, and finished in the top five in the three events prior to it.
Not all the news was good out of Texas Thursday.
No. 2 ranked Stacy Lewis of The Woodlands, near Houston, had a day to forget. She had five bogeys over her first seven holes and finished with a round of 4-over 74.
Lewis, winner of the British Open, saw her U.S. team taken apart last weekend by the Europeans at the Solheim Cup, in Denver.
It was the first time the Euros had taken the trophy on U.S. soil, and Lewis said the letdown crept into her game in Edmonton.
"I played terrible all day," she said. "I didn't make any putts. I didn't hit the ball very good and the start just didn't help.
"I was tired out there. Mentally I wasn't in it. Just coming off the last week is still tough."
Anything to work on prior to Friday? she was asked.
"No, honestly I need to get away from it right now. Probably the best thing I could do is walk away."
Late in the day tournament officials announced Lewis had withrdawn due to illness.
Americans Christie Kerr and Paula Creamer carded four-under 66s to tie for 4th.
World No. 1 Inbee Park overcame a disastrous start to finish three-under 67 and in a four-way tie for sixth.
Park, starting on the back nine, bogeyed holes 10 and 12 before settling down and chewing up the course.
She said the bogeys were not necessarily bad shots.
"Out of the rough, it is just hard to tough to judge how much release you're going to get. (It was) just a couple of bad bounces," said Park.
Tied with Park was Jennifer Kirby of Paris, Ont.
Kirby, who turned pro earlier this year, said playing in the LPGA's Manulife Financial Classic last month in Waterloo, Ont., (finishing tied for 41st) helped ease the nerves in front of crowds in Edmonton.
"I felt very comfortable out there and ended up making a few putts and a good round," said Kirby. She is ranked 560th in the world, but tabbed as one of the future stars of Canadian golf.
There are 155 players vying for US$2 million in prize money, with $300,000 going to the winner.
With Ko still classified as an amateur, she is not eligible for the prize money. Should she win Sunday, the cash would go to the second-place finisher.
Notes: Canadian Lorie Kane of Charlottetown carded 1-over 71, good for six strokes back. In 14 events this year, Kane has missed the cut nine times and never finished higher than 41st.Suggest a correction