The golf world will descend on Long Island's East End starting today for the U.S. Open at Shinnecock Hills in Southampton. Organizers are expecting 40,000 people each day, with around 150,000 for the entire week. Here's everything you need to know. The U.S. Open, organized by the United States Golf Association, is one of golf's four major annual championships. This event is famous for being one of the hardest to win. What makes it so unique is that both professionals and amateurs compete.