Borders write new political geographies. They also bring older fears and anxieties into sharper relief. Perhaps nowhere in the post-Ottoman world was this more the case than in historic Greater Syria, today the Syrian and Lebanese Republics, Jordan, Israel and the Occupied Palestinian Territories. Drawing on Syrian newspaper accounts from the 1930s as well as French and British trade agreements, this paper illustrates the fraught process of negotiating and defining a post-Ottoman space. The borders that would outline the new nation states in the region produced not only new political arrangements, but reordered the economic and social environments of this formerly unified space.Whereas the appearance of new borders elsewhere provoked massive transfers of population with commensurate levels of human suffering, the experience in Greater Syria and in the space that would become the Syrian Republic was remarkable for the ambivalent and conflicting reactions these new borders provoked among contemporaries. Borders were at once outrages perpetrated on the Syrian nation by colonial interlopers dividing its constituent parts, strategic frontiers of little concern to anyone save colonial officers, and prized redoubts that formed crucial buttresses against enemies close to home, keeping them out. The ways in which historical actors in Syria navigated borders that were in places extremely permeable and in others hard, fast and bristling with armed defenders defined in large measure the region’s political and economic relationships of the subsequent decades. In this way, investigating contemporary perceptions of borders, how they were imposed, and general sentiment to them, promises to illuminate both the historical origins of the space modern Syria emerged from and its place in the future.