What is the official name for America’s 250th-anniversary observance?

The official name for America’s 250th-anniversary observance is the United States Semiquincentennial.

“Semiquincentennial” combines word parts associated with half of five hundred, or 250 years. The term identifies the anniversary of the United States Declaration of Independence in 2026. America250 is the public-facing name used by the congressional commission and its nonprofit partner for the nationwide commemoration.

The terminology can be confusing because several anniversary words sound alike. A centennial marks 100 years, a sesquicentennial marks 150 years, a bicentennial marks 200 years, and a tricentennial marks 300 years. The 250th anniversary does not have the same everyday familiarity as “bicentennial,” so “Semiquincentennial” is often explained in program materials.

Other terms have appeared in historical discussion, including “sestercentennial” and “quarter millennium.” America250’s principal official designation, however, is United States Semiquincentennial.