The
San Francisco volcanic field is an area of
volcanoes in northern
Arizona, north of
Flagstaff, USA. The field covers 1,800 square miles (4,700 km²) of the southern boundary of the
Colorado Plateau. The field contains 600 volcanoes ranging in age from nearly 6 million years old to less than 1,000 years (
Miocene to
Holocene), of which
Sunset Crater is the youngest. The highest peak in the field is Humphreys Peak, at Flagstaff's northern perimeter: the peak is Arizona's highest at 12,633 feet (3,851 m) and is a part of the San Francisco Peaks, an extinct
stratovolcano complex.