Deep mapping is an emergent scholarly practice that makes arguments spatially, frequently in the form of a map. This chapter puts deep mapping practices into an historical context with geography and cartography to show how practitioners have taken theoretical liberties with maps and geographic information systems (GIS) by challenging their claims to indexicality and objectivity. First, the chapter outlines theoretical interventions of the last 30 years that have challenged our commonplace ideas of space and place. It then examines three specific examples of deep mapping projects: The Edmonton Pipelines Project, a research cell at the University of Alberta; The London Streetmuseum app, a locative media application that annotates contemporary London with historical images and narratives; and HyperCities, a UCLA-based project and platform that allows scholars to build deep maps without having to acquire prohibitive technological skills. Bringing these three projects together shows the different paths and practices that deep mapping can take, self-consciously producing spatial arguments as situated knowledge.