What formal term describes the United States’ 250th anniversary, commemorated by America250 in 2026?

The formal term for the United States’ 250th anniversary, commemorated by America250 in 2026, is the semiquincentennial.

The word combines “semi,” meaning half, with “quincentennial,” meaning a 500th anniversary. Together, the term denotes 250 years. The observance marks the anniversary of the United States Declaration of Independence and the revolutionary movement that created the country.

America250 is the public-facing name associated with the United States Semiquincentennial Commission, established by Congress to coordinate nationwide and international commemorations. “Sestercentennial” and “quarter millennium” are also used as descriptive alternatives, but semiquincentennial is the formal term most closely associated with the 2026 observance.

The 2026 anniversary follows the United States Bicentennial in 1976, which marked 200 years since independence. It is distinct from the 250th anniversary of the Constitution, which will occur in 2037, because the Constitution was signed in 1787.