This dissertation focuses on publics and the public sphere to argue that communication theory should investigate connections across discourse, space, and practice in the creation and maintenance of publics. I chose antebellum Philadelphia as my test case for two reasons. First, theorists such as Jurgen Habermas have identified the antebellum period as the time when the public sphere ceased to be maintained through face-to-face relations and became connected by means of the news media. Second, tremendous social and political conflict also characterized this period when categories considered by communications theory to be discursively constructed, such as "race" and "nation," were contested and revised. The majority of archival evidence tells a different story, one in which spatial relations and material conditions defined the public, and the act of being in public was a contested mode of political communication. Antebellum Philadelphians attempted to define, shape, and communicate public opinion through the development of the material city and the spatial practices of its inhabitants.