The United States celebrated its bicentennial in 1976, exactly 50 years before America250.
A bicentennial marks 200 years, so the 1976 observance commemorated the 200th anniversary of the Declaration of Independence’s adoption in 1776. The celebrations included ceremonies, exhibitions, parades, and special national symbols.
The 1976 milestone was the previous major nationwide anniversary in the same sequence. The 2026 semiquincentennial follows it by half a century and marks 250 years instead of 200.
The terms can be easy to mix up. A centennial is a 100th anniversary, a sesquicentennial is a 150th, a bicentennial is a 200th, and a semiquincentennial is a 250th. The United States’ next 300th anniversary will be its tricentennial.