Which dinosaur was the first to be mounted for public display?

The dinosaur first mounted for public display was Hadrosaurus.

In 1868, a reconstructed skeleton of Hadrosaurus foulkii became the first dinosaur skeleton mounted for public exhibition. The display was assembled at the Academy of Natural Sciences of Philadelphia, with paleontologist Joseph Leidy collaborating with the sculptor and naturalist Benjamin Waterhouse Hawkins.

The story began in Haddonfield, New Jersey, where large bones were noticed in a marl pit in 1838. William Parker Foulke reopened the site and excavated much of the skeleton in 1858. Leidy recognized the importance of the discovery and reconstructed Hadrosaurus as a biped, challenging the period’s common image of dinosaurs as sprawling, lizard-like animals.

The mount was historically important because it presented a relatively complete dinosaur skeleton to a broad public audience and helped make dinosaur science popular. It was not a fully complete fossil: missing elements, especially the skull, were supplemented with plaster and artistic reconstruction. Diplodocus later became famous for dramatic museum mounts, but Hadrosaurus holds the earlier public-display milestone. It became New Jersey’s official state dinosaur in 1991.