What was the name of the previous nationwide U.S. anniversary celebrated in 1976, before America250?

The previous nationwide U.S. anniversary before America250 was the United States Bicentennial.

The bicentennial marked the 200th anniversary of the adoption of the Declaration of Independence and culminated on July 4, 1976. It was celebrated through parades, exhibitions, fireworks, naval events, educational projects, commemorative products, and historical reenactments throughout the country.

Planning involved the American Revolution Bicentennial Commission and later the American Revolution Bicentennial Administration. President Gerald Ford took part in major national observances, including events in Philadelphia and Washington, D.C. The celebration also produced special United States coins, including redesigned quarters, half dollars, and dollars.

The 1976 observance is a useful comparison for America250, but the names describe different anniversaries: bicentennial means 200 years, while semiquincentennial means 250 years. The intervening 50 years also changed how national commemorations are organized, with broader participation by states, territories, museums, and community groups.