How Old Is the Grand Canyon? ~5–6 Million Years as a Canyon

The Grand Canyon as a distinct canyon carved by the Colorado River is geologically young: approximately 5–6 million years old.

Nuance:

• Rock Age: Exposed layers range from 270 million years (Kaibab Limestone) at the rim to 1.8 billion years (Vishnu Basement Rocks) at the bottom.
• Incision Timing: The Colorado River established its current course through the Kaibab Plateau ~5–6 Ma, integrating older paleocanyons.
• Debate: Some studies suggest precursor canyons (e.g., "Ancestral Grand Canyon") existed 17–70 Ma, but the modern through-going canyon is <6 Ma.

So while the rocks are ancient, the canyon itself is a geologically recent feature.