Mining loomed large in colonial Andean society. In the eighteenth century, projects to reform existing mines and establish new ones were increasingly accompanied and shaped by mapping. Numerous mining maps from the colonial Andes are preserved in archival collections. This study examines the roles that these frequently overlooked maps played in the exploitation of the underground. How were they made and used, and what effects did they have? What do these maps reveal about colonial understandings of the subterranean? How might they enrich understandings of the Spanish American Enlightenment? These questions are explored through the prism of small stories about the mapping of mining sites in late colonial Bolivia, Peru, Chile, and Ecuador.