What name is used for the 250th anniversary of the United States, commemorated nationally by America250?

The 250th anniversary of the United States commemorated nationally by America250 is called the United States Semiquincentennial.

The word semiquincentennial refers to a 250th anniversary. Its parts combine “semi,” meaning half, with “quincentennial,” meaning a 500th anniversary. Because the term is uncommon, the celebration is more widely recognized through the America250 name and branding.

Other labels have also been proposed or used, including sestercentennial, bisesquicentennial, and quarter millennium. These alternatives can create confusion, but they describe the same numerical milestone. The event commemorates the 250th anniversary of the Declaration of Independence and the founding era of the United States.

The United States previously marked its centennial in 1876, sesquicentennial in 1926, and bicentennial in 1976. The semiquincentennial is therefore the next major 50-year increment after the bicentennial. America250 planning began through a federal commission established in 2016.