Ten groups from the afternoon tee times finished playing on the 6,353-yard Echo Lake Country Club course, but 48 golfers were still on the course when lightning halted play.
Tournament officials said stroke play will resume at 7:30 a.m. Wednesday, and only one round of match play will be played later in the day. The rest of the schedule has not been announced.
After shooting a 3-under 70 on Monday, Park had five birdies, a bogey and one double-bogey. Park, born in Korea and currently living in Eustis, Fla., is at 5-under 141 overall.
Chris Brady of Apex, N.C., and Paula Creamer of Pleasanton, Calif., are tied for second at 150.
No players from the morning group other than Park were able to break par. Eom Ji Park of Canada and Amanda McConnell of Grand Blanc, Mich., posted 1-over 74s.
In-Bee Park, starting on No. 10, began with five straight pars before birdieing the 448-yard par-5 15th. She then birdied No. 18 ' a 385-yard par 4. The day was capped at the par-4 ninth with an impressive par save in which Park got up and down by draining an 11-foot putt.
'She can hit it 240 yards,'' said her coach Charlie Yoo. 'She has been striking the ball well and hitting a lot of fairways.''
The U.S. Girls' Junior is one of 13 championships conducted by the USGA each year, 10 of which are strictly for amateurs. It is open to female amateur golfers who have not reached their 18th birthday before July 27, 2002, and have USGA Handicap Indexes not exceeding 18.4.
After the completion of stroke play Wednesday, the U.S. Girls' Junior Championship field will be reduced to 64 players for match play.