Sierra Grande is an extinct stratovolcano in northeastern New Mexico that rises 2,200 feet above the surrounding plain.

On a clear day, Sierra Grande can be seen from as far away as Texline, Texas, as well as from the summits of the Culebra Range in southern Colorado and northern New Mexico.

The eastern slopes of Sierra Grande are the easternmost point in the United States with an elevation of more than 8,000 feet (2,400 m) above sea level,[3] and the peak is the highest in the United States east of 104 degrees west.

[10] Sierra Grande is the largest volcano in the Raton-Clayton volcanic field.

The volcano is largely composed of two-pyroxene andesite, a rock type found almost nowhere else in the Raton-Clayton volcanic field.