
Taken near the entrance of Hawai`i Volcanoes National Park (which is now closed) on May 15, 2018, at 11:28 am.
MORTON GNEISS
Morton, Minnesota
Oldest Rock in the United States — 3.524 billion years old
MORTON GNEISS
Morton, Minnesota
Oldest Rock in the United States — 3.524 billion years old
Kilauea Volcano
10 Questions About the Earth—
and the Geology of North America.
Science — History — Biography
WHERE IS THE MOST RECENT VOLCANIC
ERUPTION IN THE EASTERN U.S.?
The youngest volcano is Mole Hill that stands 400 feet above the surrounding landscape and that is located in the Shenandoah Valley a mile west of Harrisonburg, Virginia. It is a rounded hill composed of basalt and is the eroded remnant of an active volcano, that is the interior plumbing of a volcano, and not the volcano itself. It was active 47 million years ago.

Mole Hill in the Shenandoah Valley west of Harrisonburg, Virginia.
Trimble Knob, another volcanic remnant, located southwest of Monterey, Virginia, is slightly older, 49 million years. The eruption of Trimble Knob and Mole Hill represent a period of volcanic activity that lasted ten million years or less.