Last year's runner-up Kelly Robbins, Hee-Won Han, Michele Redman, Michelle Ellis and Gloria Park finished tied for third at three-under-par 69.
Golden, who earned her first career victory on the LPGA Tour at the State Farm Classic at The Rail Golf Club last year, teed off at the 10th Thursday and got off to a quick start with two birdies over her first four holes.
At the par-4 18th, Golden ran into trouble for the only time in her round after she two-putted from 10 feet for bogey. She came right back, however, and hit a 5-iron to 12 feet for birdie at the first.
Golden moved to 3-under with an eight-foot birdie at the eighth and took the outright lead at the very next hole. She hit a 3-wood to reach the green at the par-5 ninth in two but was left with almost 70 feet to the cup. She lined up the putt and ran home the long eagle for sole possession of first place at Summerlea Golf and Country Club.
'I looked at it from the back and it just didn't look like it was going to break very much,' said Golden. 'Just the right line and just the right speed and it just went in dead center. Those are the ones that make you want to play again.'
Golden, who turned pro in 1992, finished tied for second at this year's ShopRite LPGA Classic for her best result of 2002.
'I've been working on being more consistent,' said the 35-year-old. 'I tend to plug along and have a couple of really, really good weeks. I would like to be really consistent and finish top-10 every week, but you can't always get what you want.'
Kim, who has been a model of consistency on tour this season with seven top-10 finishes and two victories, collected four birdies for a bogey-free round of 4r-under-par 68.
'I just had a very good shot and very good short game today,' said the diminutive Korean. 'So I'm enjoying the round.'
Marisa Baena, Dorothy Delasin, Rosie Jones, Jung Yeon Lee, Catriona Matthew, Laurie Rinker-Graham and Moira Dunn finished three strokes off the lead at 2-under-par 70.
Karrie Webb, winner of the Women's British Open last week, managed one birdie and one bogey for a round of even-par 72.
Full-field scores from the Bank of Montreal Canadian Women's Open