Snedeker, helped by a run of five birdies in six holes around the turn, fired a four-under-par 68 at the hosting Pebble Beach Golf Links on a glorious sun-splashed winter's day.
That left him at 12-under 202 and level with PGA Tour rookie Hahn who carded a six-under 66 at Spyglass Hill, the most difficult of the three venues being used this week.
American Chris Kirk was a further stroke back after a six-under 64 at Monterey Peninsula but it was not a good day for defending champion Phil Mickelson who triple-bogeyed the last at Pebble Beach for a 73 to finish right on the cutline.
Snedeker was delighted to remain on track for his first victory of the year, despite losing momentum over the closing stretch where he failed to take advantage of a few good birdie opportunities.
"I played great, pretty much from start to finish," he told CBS. "A couple of hiccups here and there but I'm in great shape going into tomorrow.
"I let probably three or four (birdie chances) slide on the back nine which I needed to make. I just need to start making some putts," added Snedeker, who has recorded three top-three finishes in his first four events on the 2013 PGA Tour.
Hahn ended his round on a rousing note with birdies on his last three holes to draw level with Snedeker at the top.
"My attitude was good today," the 31-year-old said. "I started off well and I just told myself I was going to give myself a lot of (birdie) looks.
"Spyglass is one of my favourite golf courses in the rotation so you can't have a bad day out there."
Snedeker, co-leader overnight with fellow American Ted Potter Jr., made a fast start to the third round with a birdie at the par-five second to move a stroke in front at nine under.
Though he bogeyed the short fifth, he rebounded in style with four consecutive birdies to reach the turn in four-under 32, three ahead of the field.
"I hit a lot of irons real close on the front nine ... and that was a great way to finish (the nine) but I didn't really make a putt," Snedeker said. "I had a bunch of six or eight-footers."
Snedeker surprisingly bogeyed the par-four 10th after finding the middle of the fairway off the tee but immediately recovered by rolling in a 12-footer to birdie the 11th.
Known as one of the best putters in the game, Snedeker missed birdie attempts from eight feet at the 17th and from 11 feet at the last to remain three shots in front.
Four-times champion Mickelson, who won last week's Phoenix Open after a dominant display in the Arizona desert, was two under for the day with three holes to play before his round unravelled.
The American left-hander ran up a three-putt bogey at 16, but then recovered by sinking a nine-footer to birdie the 17th before making a mess of the last.
Mickelson hit two shots into the ocean while playing the 18th, slipping on rocks while looking for his errant drive, before completing his back nine in two-over 38.
"I got lucky I didn't get hurt," the world number 10 said. "It was a beautiful day here at Pebble, we got perfect weather and I just couldn't get going. And then to finish with a triple, it doesn't feel great."
The three-round cut fell at one-under 213 with former world number one David Duval and triple major champion Padraig Harrington of Ireland among those failing to advance.
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