The United States Semiquincentennial will be the 250th anniversary of the Declaration of Independence of the Thirteen Colonies in 1776. The United States Semiquincentennial is the 250th anniversary of the establishment of the United States of America (1776-2026). It will occur in 2026. Observances are already being planned. On July 4, 2026, people across the nation and the world will commemorate 250 years of American independence. It’s going to be a star-spangled event and it is already considered the largest celebration in U.S. history!