Researchers have noted and studied the finely formed manos and metates of the Casas Grandes region of northern Mexico, but little is known about how and where they were produced. During a survey project in 2013, we located a quarry, the first discovered in this region, where grinding stones were manufactured using a suite of stone tools. We report the morphology of the site, the tool kit of the metateros (metate makers), and ethnoarchaeological implications resulting from the study of modern metateros that can aid in the interpretation of prehistoric ground stone quarries.