The unique feature of geographic information systems (GIS) and other forms of historical data visualization is the capacity to hold and display large amounts of data associated with spatial reference points. This software can display all data for a given point, a single variable for all points, or, most important, any combination of variables across all reference points. In doing so, these systems bring to the screen instantly and cheaply a display of information once visible only in paper form, drawn slowly and expensively, first by cartographers and then by vector plotters. This project deploys GISto help us understand the intersection of social and political life in nineteenth-century Alexandria, Virginia, and Newport, Kentucky-medium-sized cities with populations under 20,000. Commercial Alexandria, with a race-based labor system, and industrial Newport, with an immigrant labor system, present an analytically useful mix of commonalities and differences.