Scholars often claim that medieval writers use Britain and England interchangeably, but Britain was a contested term throughout the period. One persistent issue was how Scotland fit within Anglocentric visions of the island it shared with England and Wales. This article traces imperialist geography in English historiography via the descriptio Britanniae (description of Britain), a trope found across the Middle Ages, and the fourteenth-century Gough Map, the first sheet-map of Britain. Scottish historians rebut the claims of their Anglocentric counterparts and demonstrate their incomplete knowledge, which they zealously supplement by inventorying Scotland’s natural abundance. In particular, the article concentrates on the remarkable celebration of Scotland’s marine life in Walter Bower’s Scotichronicon (ca. 1447). Attending to the long history of these debates both reveals and counteracts the Anglocentrism of insular literary history.