The United States Semiquincentennial marked the 250th anniversary of American independence. The term “semiquincentennial” denotes a 250-year anniversary, combining “semi,” meaning half, with “quincentennial,” a 500-year anniversary.
The anniversary was tied to the Declaration of Independence, adopted by the Second Continental Congress on July 4, 1776. That document announced that the Thirteen Colonies regarded themselves as free and independent states rather than subjects of the British Crown.
The 250th anniversary followed earlier national milestones: the centennial in 1876, the sesquicentennial in 1926, and the bicentennial in 1976. A common confusion is to treat the semiquincentennial as the anniversary of the Constitution or the Bill of Rights. Those documents came later—the Constitution was drafted in 1787 and ratified in 1788—so neither defines the 2026 milestone.