The Grand Canyon is a natural formation on Earth, located in Arizona. By the 24th century, the Grand Canyon has been a popular tourist destination for several hundred years.
Jonathan Archer had asked T'Pol if she had visited the Grand Canyon as well as Big Sur Aquarium during her time on Earth, to which she had not.(ENT episode & novelization: Broken Bow)
As a child, Leonard McCoy visited the Grand Canyon with his grandfather, T.J. McCoy. (TOS short story: "Make-Believe") Years later, he spent two weeks rafting down the Grand Canyon just before starting his assignment on the USS Enterprise. (TOS novel: Enterprise: The First Adventure)
Shortly after meeting Siddhe, Christopher Pike decided to show her his home world. One of the sights that they visited was the Grand Canyon. (TOS novel: Burning Dreams)
Edward Janeway referred to the Grand Canyon as "Earth's biggest ditch." His daughter Kathryn Janeway felt the area was too dusty, preferring farm country such as that around Bloomington, Indiana. (VOY episode: "Imperfection")