The Louisiana Purchase Exposition, informally known as the St. Louis World's Fair, was an international exposition held in St. Louis, Missouri, United States, from April 30 to December 1, 1904. Local, state, and federal funds totaling $15 million were used to finance the event. More than 60 countries and 43 of the then-45 American states maintained exhibition spaces at the fair, which was attended by nearly 19.7 million people.