The Raton-Clayton volcanic field is a broad volcanic region in northeastern New Mexico made up of many separate vents rather than a single mountain. At the northeastern end of the Jemez Lineament, it records magma rising along a zone of crustal weakness and producing about 125 cinder cones, domes, volcanic necks, and the shield volcano Sierra Grande over millions of years. Its volcanism evolved through three phases, with changing magma compositions and landforms such as Red Mountain and Sierra Grande. The youngest known eruption, at Capulin Peak about 60,000 years ago, shows that this is the easternmost volcanic area in the United States not considered extinct.