The Boot Heel volcanic field is located in the Bootheel region of southwest New Mexico, adjacent areas of southeastern Arizona, and northwest Mexico. The field covers an area of more than 24,000 km². The field includes nine volcanic calderas ranging in age from 26.9 to 35.3 Ma. Extrusive products include rhyolitic ignimbrites along with basalt, andesite, and rhyolite lava flows.