Chapter 44 of Moby-Dick (“The Chart”) includes a footnote comparing Ahab’s plan to track Moby Dick across the globe with Matthew F. Maury’s efforts to chart the winds and currents of the oceans and produce an accurate “whale chart.” This article unpacks the effects produced by the addition of the footnote in the chapter and uses it as a starting point for examining Ahab’s charts and discussing the interactions between map and text. At first sight, Maury’s chart is used as a stable reference point that reinforces the verisimilitude of Ahab’s plan. A comparison of Ahab’s use of nautical charts with actual documents used by whaling captains, though, reveals a disjunction between his cartographic ratiocinations and Maury’s work. Yet the most significant detail in the footnote might be the fact that Maury’s chart is “in course of completion”: far from being a definite document that the text can rely on to bolster the plausibility of Ahab’s method, the chart remains unseen—and even unseeable, since the version described in the footnote was never produced in reality. The “deictic” gesture performed by the footnote duplicates Ahab’s yearning for an object that constantly eludes him.