What is the official term for America's 250th anniversary, as used by the United States Semiquincentennial Commission?

The official term for America's 250th anniversary is the United States Semiquincentennial.

“Semiquincentennial” combines Latin-derived elements associated with half and five hundred, producing a term for 250 years. It is less familiar than “bicentennial,” which describes 200 years, but it is the principal formal name used for the 2026 commemoration.

Other terms have appeared, including sestercentennial, quarter millennium, and bisesquicentennial. These alternatives are valid historical labels, but they are not the main name used by the federal anniversary commission or the America250 initiative.

The event commemorates the 250th anniversary of the Declaration of Independence's adoption. America250 is the public-facing name connected with the national effort, while the United States Semiquincentennial is the formal historical designation.