The US Chess Championship is an invitational tournament organized by the United States Chess Federation to determine the country's chess champion. It is the oldest national chess tournament. The event originated as a challenge match in 1845, but the champion has been decided by tournament play under the auspices of the USCF since 1936. The tournament has fluctuated between a round-robin tournament and a Swiss system. From 1999 to 2006, the championship was sponsored and organized by the Seattle Chess Foundation and featured a larger body of competitors, made possible by the change to a Swiss-style format. After the Foundation withdrew its sponsorship, the 2007 and 2008 events were held in Stillwater, Oklahoma, still as a Swiss system, under tournament director Frank K. Berry. Rex Sinquefield's Saint Louis Chess Club has hosted the championship since 2009. Since 2014, the championship has used a round-robin format.

The United States Chess Federation is the governing body for chess competition in the United States and represents the U.S. in FIDE, the World Chess Federation. US Chess administers the official national rating system, awards national titles, sanctions over twenty national championships annually, and publishes two magazines: Chess Life and Chess Life for Kids. The USCF was founded and incorporated in Illinois in 1939, from the merger of two older chess organizations. It is a 501(c)(3) non-profit organization headquartered in St. Louis, Missouri. Its membership as of 2020 as COVID hit was 97,000; as of 2024 the membership was 112,000.