What is the formal name for America's 250th-anniversary celebration in 2026?

The formal name for America’s 250th-anniversary celebration in 2026 is the United States Semiquincentennial.

The word semiquincentennial combines semi-, meaning half, with quincentennial, meaning a 500th anniversary. Together, the term identifies a 250-year milestone. Other names have also appeared, including sestercentennial, bisesquicentennial, and quarter millennium, but semiquincentennial is the standard formal label.

The anniversary centers on July 4, 2026, 250 years after the Second Continental Congress adopted the Declaration of Independence. America250 is the public-facing name used by the congressionally established commission responsible for planning and coordinating the commemoration.

The event is not called a bicentennial because that word specifically describes a 200th anniversary. The 1976 celebrations were therefore the United States Bicentennial, whereas the 2026 milestone requires a different term.