The Sentinel Plain volcanic field, also known as the Sentinel-Arlington volcanic field, is a volcanic field in Arizona made up of monogenetic vents, each typically formed by a single eruption. Its lava is alkali basalt, placing it among Arizona’s basaltic volcanic landscapes. Rather than being a single mountain or a long-lived volcano, it was built through separate small eruptions that collectively created the field. Its importance lies in this geology, which reflects repeated small volcanic events and shows how parts of Arizona’s landscape were formed by multiple distinct eruptions instead of one enduring volcanic center.