Beginning in the 1850s, but especially between the 1880s and 1920s, the Ottoman Empire advertised and granted hundreds of concessions for infrastructure and extraction projects ranging from railway construction to chromium mining to marsh drainage. While historians generally agree that concessions represented and facilitated European financial domination over the Ottoman Empire, most scholars of concessions have focused on specific projects, usually large foreign-dominated ones. This paper argues that rather than being primarily instruments of European empire, we should understand concessions as a way for the Ottoman Empire to assert territorial sovereignty. A growing body of literature has argued that the prevailing perception of Ottoman sovereignty as deficient and diminishing in the nineteenth century does not accurately reflect Ottoman uses of law – from autonomous provinces to nationality regulations – to assert sovereignty both domestically and internationally. This paper brings concessions into that conversation by re-examining what a concession is. First, I explore changing legal uses of the word imtiyaz, which referred primarily to grants of rights to minority communities before it came to refer to concessions. This genealogy suggests that the Ottoman concession regime emerged from a longer, ongoing effort to assert and demarcate state authority, and as such reflected the changing priorities of Ottoman authorities. The paper then goes on to examine the complex of documents which characterized Ottoman concessions. Although we often use the shorthand “contract” to refer to concessions, they were actually constituted by a much broader range of legal artifacts from regulations to corporation specifications to memos. I will focus specifically on maps. Concessionaires were invariably required to produce maps of the concession area, which were to be turned in to the government before anything else. Mapping is important in part because historians have identified mapping as a key tool nineteenth-century empires used to assert territorial sovereignty – and something that was largely missing in the Ottoman Empire. Concession maps are territorially scattered and limited in scope, but nonetheless represent the kind of detail Ottoman authorities supposedly undervalued. If concessions were about asserting sovereignty, how do concession-maps help us understand that project? Building on a literature which views geography and mapping as entangled with law, the paper argues that maps were crucial to the imperial assertion of sovereignty through concessions, while offering insight into the lumpiness and unevenness of modern sovereignty.