What is the United States’ 250th anniversary officially called?

The United States’ 250th anniversary is officially called the United States Semiquincentennial.

The term combines “semi,” meaning half, with “quincentennial,” meaning a 500th anniversary. It therefore describes half of five centuries, or 250 years. The anniversary commemorates the Second Continental Congress’s adoption of the Declaration of Independence on July 4, 1776.

The celebration is also known by several less common names, including the Bisesquicentennial, Sestercentennial, and Quarter Millennium. “Semiquincentennial” is the name most closely associated with the national commemoration and the America250 initiative.

The event is distinct from the United States Bicentennial, which marked 200 years in 1976. It is likewise not the country’s 250th birthday in the sense of a single constitutional founding date; the anniversary centers on the 1776 declaration of independence and the political creation of the United States.