The first round of the 126th U.S. Open began on June 18, 2026, at Shinnecock Hills Golf Club on Long Island. World No. 1 Scottie Scheffler, celebrating his 30th birthday, aimed for a career Grand Slam, while Rory McIlroy sought his seventh major title. The tournament featured a strong amateur group, including NCAA Men's Division I Champion Preston Stout and 17-year-old Miles Russell. The USGA announced plans to manage course conditions due to expected high winds.
Keith Mitchell had a remarkable round, starting with a challenging back nine where he was six over par at one point. However, he rebounded on the front nine, finishing with a score of even-par 70, which included a 29 on the front nine. This marked only the seventh instance in U.S. Open history of a player carding a 29 over nine holes.
Wyndham Clark, a former U.S. Open champion, took an early lead with a score of six under through 16 holes. Other notable performances included Scheffler with a two over 72 and McIlroy finishing at one under par. McIlroy commented on the day's conditions, stating that scoring around even par was commendable given the challenges presented by the course.