Play rotated over historic Merion Golf Club and Philadelphia Country Club and Lepp posted his score on Tuesday at the much easier Philadelphia Country Club.
'It's an honor to win the medal, but what matters most is the match play,' said Lepp, a senior at the University of Washington. 'This tournament is all about match play. I'm happier that I'm just playing well and I feel confident.'
The only other player under par through two rounds is Korey Mahoney, who carded a 3-under-par 67 at Philadelphia Country Club. He is at one-under- par 139 through the opening portion.
Nineteen players have to return Wednesday morning for the remaining 17 spots in the match-play part of the tournament. The match-play portion of the tournament will take place at Merion.
First-round leader Charlie Beljan fired a 64 on Monday at Philadelphia Country Club, but cooled on Tuesday. He struggled to a 76 at Merion and is tied for third place. Jay Choi shot a 72 at Merion in the second round and joined Beljan at even-par 140.
Lee Williams (69), Austin Eaton III (70), Joseph Sykora (72) and Keven Fortin Simard (69) are knotted in fifth place at 1-over-par 141.
Ben Kishigian (68), Emilio Dominguez (72), Tyler Hitchcock (68) and Andrew Parr (74) are tied for ninth at plus-2.
Luke List lost the last four holes in 2004's final match against Ryan Moore, but List won't be making it that far in 2005. He shot a 1-under 69 on Tuesday at Philadelphia Country Club, but that was after an 80 on Monday at Merion. He missed the cut by three strokes at 9-over-par 149.
The match-play portion of the event begins on Wednesday. The second and third round matches are scheduled for Thursday, with the quarterfinals slated for Friday. Saturday will feature semifinal play while the 36-hole final will take place on Sunday.