What is the official term for America250’s 250th-anniversary celebration?

America250’s 250th-anniversary celebration is officially called the Semiquincentennial.

The word combines “semi,” meaning half, with “quincentennial,” meaning a 500th anniversary. Together, the term describes half of a millennium, or 250 years. It is the formal name commonly used for the United States’ 2026 anniversary observances.

The celebration marks the 250th anniversary of the Second Continental Congress adopting the Declaration of Independence in 1776. July 4, 2026, is therefore the central anniversary date. America250 is the public-facing name associated with the national commemorative effort.

A common mix-up is “bicentennial,” which means 200 years and referred to the 1976 anniversary. “Sesquicentennial” means 150 years, while “tricentennial” means 300 years. The term “Semiquincentennial” is unusual because many countries use more familiar round-number anniversary labels instead.