What was the name of the first official world's fair held in the United States in 1876?

The first official world's fair held in the United States in 1876 was the Centennial Exposition.

Also called the Centennial International Exhibition, it took place in Philadelphia to celebrate the 100th anniversary of the Declaration of Independence. Its formal title was the International Exhibition of Arts, Manufactures, and Products of the Soil and Mine.

The exposition demonstrated the United States' industrial and technological ambitions to international visitors. Its displays included machinery, manufactured goods, agricultural products, and new inventions. The fairgrounds covered a large section of Fairmount Park along the Schuylkill River.

It is easy to confuse the Centennial Exposition with later American world's fairs. Chicago hosted the World's Columbian Exposition in 1893, while Philadelphia hosted another anniversary fair, the Sesquicentennial Exposition, in 1926.