The United States Open Championship, commonly known as the U.S. Open, is the annual open golf tournament of the United States. It is the second of the four major championships in golf and is on the official schedule of both the PGA Tour and the European Tour. It is staged by the United States Golf Association in mid-June, scheduled such that the final round is always played on the third Sunday, which is Father's Day.

The U.S. Open is staged at a variety of courses, set up in such a way that scoring is very difficult with a premium placed on accurate driving. U.S. Open play is characterized by tight scoring at or around par by the leaders, with the winner emerging at just under par. A U.S. Open course is seldom beaten severely, and there have been many over-par wins. Normally, an Open course is longer than normal and will have a high cut of rough (termed "Open rough" by the American press and fans), hilly greens (such as at Pinehurst No. 2 in 2005, which was described by Johnny Miller of NBC as "like trying to hit a ball on top of a VW Beetle"), and pinched fairways.