How Markets Converged and Persisted in the Nineteenth Century U.S.: A Data Story Mapped from High-Frequency, Town-Level Postal Data

Mengyue Zhao, University of Oxford

This paper seeks to assess the geographic scope of social, economic, and political activities, specifically delineating the geographical boundaries of markets in the United States between 1849 and 1871. To achieve this, this study utilizes a dataset comprising 191,928 records of postal revenues at the town level. Notably, the spatial dimension of economic activities during this era has been relatively overlooked, even within the field of Economic Geography. Traditionally, economists have conceptualized economic activities as constrained by artificial boundaries like state or county borders or characterized by vague geographical designations such as "the Mississippi Valley" or "the Great Plains." In contrast, this paper takes a novel approach by defining the extent of markets based on the concentration of high levels of human activity at a finely detailed geographical scale and high frequency, rather than relying on predefined borders. Consequently, this methodology aims to explain how markets converged (came together) and endured (stayed together) over time. This paper introduces a statistically rigorous method for using postal data to delineate the geographic contours of markets. Postal data is particularly valuable for this purpose due to its micro-level granularity, government-issued uniformity across time and space within the United States, compatibility with computer systems, and its relatively untapped potential as an analytical tool. I digitize, clean, geocode, and analyze a bi-annual, national-scale postmaster compensation dataset in this study. It's worth noting that postal revenue can be inferred from this compensation dataset, as the Federal Government's formula directly correlates local postmaster compensation with postal revenue. This comprehensive dataset covers all towns, cities, and populated areas in the country with post offices from 1813 to 1881.

No extended abstract or paper available

 Presented in Session 35. Land Cessions, Town Settlements, and the Growth of Markets