This paper investigates the relationship between transport infrastructure and agricultural productivity in the Antebellum United States (1840–1860). Leveraging a novel dataset of county-pair transport costs, we utilize time-, region-, and direction-specific freight rates and newly digitized road network to understand how declining transit costs reshaped the agrarian landscape and agricultural production. These data allow for a rigorous evaluation of what we can call an antebellum "place-based" transport policies and their heterogeneous effects on antebellum regions. We use minimum spanning tree approach to construct a plausibly exogenous transportation network which is used to assess the causal impact of transportation infrastructure on antebellum agriculture.

Our first set of findings reveal that the impact of canal construction was not uniform, showing considerable variation across different geographic regions. Notably, in the Middle Atlantic, the introduction of canals catalyzed a significant reallocation of resources away from wheat production, signalling a shift in comparative advantage. While canals laid the groundwork, railroads exerted the most transformative influence during the 1850s. In the final decade preceding the Civil War, the expansion of the rail network drove a broad reallocation away from traditional grain production, as improved connectivity facilitated deeper market integration and specialization. By accounting for the nuances of freight directionality and regional specificity, this study provides new evidence on how infrastructure-led cost reductions altered land use and productivity patterns in the nineteenth-century U.S. economy.