What was the name of the previous major national anniversary celebrated in 1976, 50 years before America250?

The previous major national anniversary celebrated in 1976 was the United States Bicentennial.

The bicentennial marked 200 years since the Second Continental Congress adopted the Declaration of Independence in 1776. Its main anniversary date was July 4, 1976, exactly fifty years before the 250th anniversary in 2026.

Celebrations took place across the United States and included parades, fireworks, historical reenactments, exhibitions, and Operation Sail, a large gathering of tall ships. President Gerald Ford participated in national observances, and Philadelphia played a central role because of its connection to the Declaration and the Continental Congress.

The bicentennial is sometimes confused with the 1876 Centennial Exposition in Philadelphia, which commemorated the nation’s 100th anniversary. The 1926 Sesquicentennial marked 150 years. The sequence is therefore centennial in 1876, sesquicentennial in 1926, bicentennial in 1976, and semiquincentennial in 2026.