What term names America's 250th anniversary, celebrated nationally in 2026?

America's 250th anniversary, celebrated nationally in 2026, is called the semiquincentennial.

The word combines “semi,” meaning half, with “quincentennial,” referring to 500 years. Together, the term describes half of a 500-year period, or 250 years. America250 is the commonly used branding for the nationwide commemoration.

Several alternative terms exist, including sestercentennial, bisesquicentennial, and quarter millennium. However, “United States Semiquincentennial” is the formal title used for the federal commemoration. The event marks the 250th anniversary of the Declaration of Independence and related founding-era history.

The naming pattern follows familiar anniversary terms. A centennial marks 100 years, a bicentennial marks 200 years, and a tricentennial marks 300 years. The previous major national milestone was the United States Bicentennial in 1976.