What is the official historical term for America’s 250th anniversary?

The official historical term for America’s 250th anniversary is the United States Semiquincentennial.

The word semiquincentennial combines “semi,” meaning half, with “quincentennial,” relating to 500 years. Together, the term describes half of a 500-year interval, or 250 years. It is one of several possible names for a quarter-millennium anniversary, but it is the standard title used for the 2026 national commemoration.

America250 is the shorter public-facing brand connected with the United States Semiquincentennial Commission. The commission was created by federal law in 2016 to plan and encourage nationwide observances.

The 250th anniversary follows the United States Bicentennial in 1976, which marked 200 years since the Declaration of Independence. A future 300th anniversary in 2076 would be called a tricentennial. These labels describe anniversaries by elapsed years, while the specific event being commemorated is the 1776 Declaration.