This chapter examines Whitman’s correspondence from a big data perspective, mapping out networks that formed around the poet’s outreach and self-promotion efforts in order to demonstrate how these are echoed in his literary output. Following the poet from the Civil War through Reconstruction to literary fame in old age, “Reading Whitman’s Epistolary Database” sheds new light on key developments in Whitman’s life and writing. Employing a variety of visualization methods and distant reading tools, the authors situate Leaves of Grass within a broader range of writing activity, one in which published poetry and prose are viewed not as separate from epistolary media and communication formats, but intimately tied to them. The chapter aims to be a starting point for a more comprehensive look at Whitman’s textual production, as well as an introduction of this still-underutilized dataset to a wider audience of Whitman scholars and digital humanists.