Naas' Jack Hume has work to do to qualify for the matchplay stages of the US Amateur after he opened with a two over 72 at Oakland Hills near Detroit.
Starting on the 10th at the South Course, he mixed two birdies with three bogeys to turn in 36, then followed a birdie at the first with bogeys at the second and ninth to end the opening day tied for 118th.
Lipscomb University junior Dawson Armstrong, 20, posted seven birdies against one bogey on the North Course in a six under 64 for a one-stroke lead over Americans Gavin Hall and Alex Smalley and Robin Petersson of Sweden.
A group of six players, including Sam Horsfield, 19, of England, fired 4-under-par 66s on the North Course to trail Armstrong by two strokes.
The top 64 after today's second qualifying round go through to the matchplay stages on Wednesday.