What anniversary does the United States Semiquincentennial, known as America250, commemorate?

The United States Semiquincentennial, known as America250, commemorates the 250th anniversary of the United States Declaration of Independence.

The anniversary counts from July 4, 1776, when the Second Continental Congress adopted the Declaration. The document announced that the thirteen American colonies regarded themselves as independent states rather than colonies within the British Empire.

A 250th anniversary is called a semiquincentennial, from Latin-derived components meaning half of five hundred. The celebration follows earlier major national anniversaries: the centennial in 1876, the sesquicentennial in 1926, and the bicentennial in 1976.

The commemoration is sometimes described more broadly as the anniversary of the United States, but its formal historical reference is the Declaration of Independence. That distinction matters because the federal government itself was created later, under the Constitution of 1787.