The San Francisco Peaks are a volcanic mountain range

Mountain range

A mountain range is a single, large mass consisting of a succession of mountains or narrowly spaced mountain ridges, with or without peaks, closely related in position, direction, formation, and age; a component part of a mountain system or of a mountain chain...

 located in north central Arizona

Arizona

Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

, just north of Flagstaff

Flagstaff, Arizona

Flagstaff is a city located in northern Arizona, in the southwestern United States. In 2010, the city's population was 65,870. The population of the Metropolitan Statistical Area was at 134,421 in 2010. It is the county seat of Coconino County...

.
The highest summit in the range, Humphreys Peak

Humphreys Peak

Humphreys Peak is the highest natural point in the U.S. state of Arizona, with an elevation of and is located within the Kachina Peaks Wilderness in the Coconino National Forest, about north of Flagstaff, Arizona. Humphreys Peak is the highest of a group of extinct volcanic peaks known as the...

, is the highest point in the state of Arizona at 12633 feet (3,850.5 m) in elevation. The San Francisco Peaks are the remains of an eroded stratovolcano

Stratovolcano

A stratovolcano, also known as a composite volcano, is a tall, conical volcano built up by many layers of hardened lava, tephra, pumice, and volcanic ash. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile and periodic, explosive eruptions...

. An aquifer

Aquifer

An aquifer is a wet underground layer of water-bearing permeable rock or unconsolidated materials from which groundwater can be usefully extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology...

 within the caldera

Caldera

A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...

 supplies much of Flagstaff's water while the mountain itself is located within the Coconino National Forest

Coconino National Forest

The Coconino National Forest is a 1.856-million acre United States National Forest located in northern Arizona in the vicinity of Flagstaff. Originally established in 1898 as the "San Francisco Mountains National Forest Reserve", the area was designated a U.S...

 and is a popular site for outdoor recreation.