What is the formal historical name of the 2026 America250 celebration?

The formal historical name of the 2026 America250 celebration is the United States Semiquincentennial.

“Semiquincentennial” combines word parts associated with half of 500, producing a term for a 250th anniversary. The event is also described by less common alternatives, including sestercentennial, bisesquicentennial, and quarter millennium. America250 is the public-facing brand used by the United States Semiquincentennial Commission.

The name can be confused with “sesquicentennial,” which means a 150th anniversary. The United States observed its sesquicentennial in 1926 and its bicentennial, or 200th anniversary, in 1976. The 2026 observance is therefore neither of those earlier milestones.

The anniversary commemorates the Declaration of Independence and the national history connected with it. Official planning began through a congressional commission created in 2016, a decade before the anniversary year.