Capulin Volcano National Monument preserves approximately 800 acres (324hectares) primarily the cinder cone volcano. More than 15 square miles (~39 km2) of associated lava flows are outside the monument boundaries.  The volcano has been well-preserved with the greatest erosion being limited to where the cone is cut by a 2-mile road that spirals its way to the crater rim.  The volcano rises to a height of 8182 feet (2495 m) above sea level, or 1300 feet (396 m) above the surrounding High Plains and at its base is 4 miles (6.4 km) in circumference.  The crater is 415 feet (126 m) deep and 1450 feet (442 m) in diameter.  The slopes of the volcano have been partially stabilized by the formation of soils, produced by the breakdown of the volcanic material by lichens and mosses.  Once these soils formed, grasses, wildflowers, shrubs and trees took root.  Chokecherry trees, which are common along the crater trails, inspired the name for this cinder cone volcano; Capulín is a Mexican-Spanish word for Chokecherry.  

The monument lies in the Raton section of the Great Plains (or Interior Plains) physiographic province—an immense sweep of country that stretches north from Mexico to Canada, and east from the Rocky Mountains.  This section of the Great Plains is characterized by volcanism.  Capulin Volcano is just one out of many volcanoes in northeastern New Mexico.  This collection of volcanoes, called the Raton-Clayton volcanic field (RCVF), is the easternmost Cenozoic—66.4 million years ago (Ma) to present—volcanic field in the United States.  The RCVF covers nearly 8000 square miles, from Trinidad, Colorado to Clayton, New Mexico, and has been active during the last 9 million years.  The eruption of Capulin volcano, ~ 60,000 years ago, is one of the most recent eruptions in the field.  The field is presently dormant with no activity in the last 30,000 or 40,000 years.  Individual volcanic centers within the field, such as Capulin Volcano, are considered extinct.