Min aja‘ib al-buldan – one of the wonders of the world. Nineteenth-century commentators agreed that Basra and the surrounding region was defined by water in a unique way. The riverine and wetlands geography of what is now southern Iraq gave the region an equally unique relationship to water transport. Looking at changes in water transport during the nineteenth century, this paper argues that the introduction of steamships in the mid-nineteenth century had significant effects on the experience and social worlds of travel in the region, and on geographies of transport and trade. The paper draws on a variety of sources – ranging from Ottoman border chronicles (seyahatname-i hüdud) to Iranian pilgrim narratives (safarnameh/ziyaratnameh) to Arabic provincial chronicles to the diaries of an Iraqi steamship employee – to analyze the relationship between steamships and space. The paper argues that southern Iraq – the region south of Baghdad along the Tigris, Euphrates, and Shatt al-Arab, and into Iran up the Karun – represented a coherent space and was recognized as such by contemporaries. The paper then examines the changing social worlds of passengers, crew, and locals in the era of steamships, touching on the gradual severance of social and economic life on board ship from that on shore, the integral role of steamships and related merchant enterprises in the dispersion of the Baghdadi Christian community, and the ways steamships solidified class divisions in regional travel. The paper concludes with a discussion of the role of steamships in new geographies of trade and transport, both in terms of their imposition of a new boundary between “internal” and “ocean-going” shipping, and in their facilitation of uneven economic and urban growth along the Tigris. Speaking to a literature dealing with technology and the global production of space, as well as addressing long-standing historiographical questions around the nature of British imperialism in the Ottoman empire and the role of religious minorities in it, the paper interrogates the nature and inevitability of a variety of spaces in late Ottoman Iraq – from the existence of a distinct social sphere aboard ship to the distinction between river and sea. Though these changes largely did not stem from Ottoman policy, they had implications for Ottoman governance. In suggesting the river basin as a starting point for investigation, the paper points to the contingent and complex roles of technological change in this land of water.