What was the United States' previous major national anniversary celebration before America250?

The United States' previous major national anniversary celebration before America250 was the United States Bicentennial.

The Bicentennial culminated on July 4, 1976, marking 200 years since the Second Continental Congress adopted the Declaration of Independence. Its observances took place across the country and included ceremonies, exhibitions, commemorative objects, and public celebrations connected with the American Revolution.

The 1976 anniversary followed earlier milestone observances. Philadelphia hosted the Centennial Exposition in 1876 for the 100th anniversary, and the city later hosted the Sesquicentennial Exposition in 1926 for the 150th anniversary. America250 follows the same numerical sequence at 250 years.

The Bicentennial is sometimes mistaken for the anniversary of the Constitution, but the national celebration centered on independence and the Declaration. The Constitution was drafted in 1787 and ratified in 1788, so its major anniversaries fall on different dates. The Bicentennial's 1976 finale also occurred during Gerald Ford's presidency.