Recent attention to the intersections between literature and geography has yielded productive new readings of old classics like Herman Melville’s Moby-Dick, though developments in scholarship on deep time, the Anthropocene, and archipelagic and oceanic studies bring new exigency to Melville’s frequent allusions to mapping in the novel. This article brings the novel’s engagement with cartographical practices at sea into clearer focus through a series of close readings framed by the extraordinary ideal of precision guiding the cartographic agenda carried out by the US Exploring Expedition (US Ex. Ex.) in the South Pacific and Antarctica from 1838 to 1842. As metaphors for land, the captured and pursued whales in the novel reflect the surveying processes undertaken by the US Ex. Ex., which sought to establish an imperial presence in the South Pacific by bringing cartographic order to the region. In addition to emphasizing the representational failures of cartography and shortcomings of nineteenth-century cartographic processes, the novel exposes the fatally-flawed ambition of the US Ex. Ex. on two fronts: first, by revealing a contradictory imperative for imperial powers to both represent and shape the cartographic subject, which often obscures (rather than clarifies) subjects surveyed in imperial relations; and second, by demonstrating how attempts to dominate the ocean and indigenous peoples through cartographic representation expose the surveyor to cartographic counterattacks. By capitalizing on the difficulty of organizing the sea into charted order, the novel issues an ominous warning for the nation, unsettling its geography and expanding borders by envisaging latent threats within representations conveying geopolitical visibility and order.