The president that died before the dinosaurs was George Washington who died in 1799.
President George Washington died in 1799, which was decades before any dinosaurs were recognized significantly.
However the dinosaurs died off before any humans were on earth, even before George Washington was born, but it was simply that the president George Washington died before the dinosaurs were scientifically recognized and not before the dinosaurs actually died.
The first dinosaur, which is known as the Megalosaurus, which first described in the year of 1842 and the term dinosaur was then coined in the year 1842.
And although early Americans did find fossils, early Americans did not understand that they belonged to any prehistoric creatures yet.
President George Washington died, in the year of 1799, which was 25 years before the first dinosaur on earth was named.
And the first dinosaur fossil that is known as the Megalosaurus was also described in the year of 1842.
Other early presidents like John Adams who died in the year of 1862 and president Thomas Jefferson who died in the year of 1826, also lived and died before the dinosaurs were recognized formally as a species.
And many of our early American presidents were also alive when the scientists thought large, unusual fossils had belonged to massive, living creatures in the unexplored regions or even to biblical giants.
President George Washington was a Founding Father and the first president of the United States, serving from 1789 to 1797.
As commander of the Continental Army, George Washington also had led Patriot forces to victory in the American Revolutionary War against the British Empire.
George Washington was elected president twice and also had served two full terms in office, from April 30, 1789, to March 4, 1797.
President George Washington was unanimously elected by the Electoral College in both the 1788–1789 and 1792 elections.
George Washington's first Term: 1789–1793
George Washington's second Term: 1793–1797
George Washington had also famously declined to run for a third term, establishing a two-term precedent for American presidents that lasted until the 22nd Amendment was ratified in 1951.