why did john Adams and Thomas Jefferson die on the same day, July 4th 1826?
It is a coincidence they died on the same day; both John Adams and Thomas Jefferson were very old when they died. The cause of death for each of them is unknown but certainly can be attributed to old age. John Adams Second President 1797-1801 Born: 30-Oct–1735 Birthplace: Quincy, MA Died: 4-Jul–1826 Location of death: Quincy, MA Cause of death: unspecified Remains: Buried, United First Par
They both died within hours of each other. That raises your good question. They each died in their own beds–Jefferson in Monticello and Adams in Quincy. They each died of old age–Adams at age 90 and Jefferson around 82. There are medical histories for these 2 presidents. Neither history indicates a common cause. There are all sorts of hypotheses that Adams spoke of his one time adversary Jefferson as he died, but there does not appear to be any proof.