Examining the category of the Insular as a key framing of US extraterritorial, inter‐oceanic power during the late nineteenth and early twentieth centuries, the paper examines two overlapping sets of geographical discourses and mapping practices – broadly characterised as geopolitical‐imperial and scientific‐governmental – that reflected US efforts to map (remap) the Philippines after 1898, beginning with the purchase of Spanish (Jesuit) geographical knowledge. Turning to the spatially extensive and, it is argued, geopolitically loaded survey and mapping sciences, including geography, ethnology, geology, forestry and geodesy, the paper explores how cartographic practices were not only integral to a more accurate representation of the islands on paper but were also linked in practice with processes of governmental knowledge production and territorial transformation. In these efforts to extend US colonial sovereignty across the archipelago during the first decade of the twentieth century, US Insular officials grappled to know the territories which they presumed to govern.