Park had two eagles and five birdies and was at 18-under 198 at the Sunrise Golf and Country Club.
"Today, probably, was almost perfect for me," Park said. "I hit the ball great and putted really good today. Couldn't ask for better weather. It was a perfect day. The conditions of the golf course were perfect. I was able to go at every pin, so I was able to play aggressive."
Suzann Pettersen of Norway had six birdies in a round of 66 to sit in second place, two shots ahead of defending champion and local favorite Yani Tseng (66).
"I feel like I left lots of birdie chances out there today," Tseng said. "I didn't putt well again today, and I just feel (I'm) very (much) struggling out there."
Catriona Matthew of Scotland had a 68 and was in fourth, another two shots back at 12-under 204. Christie Kerr (67) of the United States was at 10 under.
More Sports Headlines
Seahawks ink QB Wilson to 4-year, $87.6M extension 3:19 p.m. M's deal Happ, Lowe at trade deadline 3:34 p.m. Seahawks open camp with WRs as position of focus Local favorite Lehman leads 3M Championships 4:34 p.m. Woods in contention at Quicken Loans after a 5-under 66 4:34 p.m. Pettersen tames Turnberry, takes 2nd-round lead 4:34 p.m. Mís notebook: Montero, Marte get the call 4:27 p.m. Kyle Busch starts drive for 4th straight win from pole 4:21 p.m.
Our new comment system is not supported in IE 7. Please upgrade your browser here.