Native Americans were the first to find it, but I think the answer your looking for is John Wesley Powell.
John Wesley was the first to navigate a boat down the Colorado River through The Canyon, an impressive feat for a man with one arm. But he was far from the first European to see it.
Garcia Cardenaz, a soldier under Coronado, saw it in 1540.
Two Spanish priests recorded seeing it a couple centuries later.
In 1861, American soldier Joseph Ives wrote about The Canyon, "This was the first, and undoubtedly the last expedition to visit this useless place."
he discovered the Grand Canyon
Coronado
The Grand Canyon was made a natural monument when the settlers discovered it, which was in 1884.
The Grand Canyon
He discovered the grand canyon
AD
no
The Native American population first discovered the Grand Canyon. The first outsiders to discover it were the Spanish.
Coronado himself never saw The Canyon, but one of his captains, Garcia Lopez de Cardenaz, was led there by a group of Hopis.
He discovered the Grand canyon and the Colorado River
He discovered the Grand Canyon.
Francisco Coranado