On 15 August 1947, the British government withdrew from India and partitioned the subcontinent to create two new nation-states: India and Pakistan. The Partition of India and Pakistan has been studied chiefly as a historical phenomenon with legacies that reach into the present. Questions of geography and space are crucial to this history, yet have hitherto received scant attention. This dissertation is a historical geography of Partition that probes the interplay of temporality and spatiality, and the historical and geographical layering, at work in the making of India and Pakistan. It treats Partition as both an event and a process, examining how the 1947 borders were rooted in a set of imaginative geographies and material geographical practices that were fashioned for and applied to the purpose of refashioning territory as part of a transfer of colonial power to independent postcolonial states and the making of new (national, religious) identities. The dissertation teases out the constitutive role of ideals and practices of territorial and cultural imagining, classification, mapping and boundary-making in this historical geography, but also highlights their contingent and contested qualities. It critically analyses and reframes Partition historiography using a range of theoretical literatures (especially critical geographical work on empire and strands of postcolonial and subaltern theory) that foster a sensitivity to the entanglements of power, knowledge, geography, expertise in the context of Partition, and draws on an eclectic range of primary sources, including the hitherto unused papers of the geographer Oskar Spate. Parts I and II trace strands of geographical and cartographic representations of ‘India' and ‘Pakistan' before 1947. Part III examines the geographies and spaces of the Punjab Boundary Commission of July 1947, in which Spate participated as an advisor to the Muslim League. Part IV points to the continued relevance of these geographies of Partition and their critical framing in this dissertation as lines of power.