International Workshop on Historical GIS

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Historical County Boundaries in GIS

John Long
The Newberry Library, USA

Nearly all scholars who study United States history and who are attracted to geographic information systems (GIS) focus chiefly on past censuses. They seek GIS-compatible base maps of historical county boundaries because counties have long been the principal geographic base units for gathering and aggregating historical statistics, and because most American counties have changed size, shape, or location several times.

Those scholars may be missing other fruitful applications of GIS. Just as there is more to GIS than the analysis and display of quantitative data, so there is more to counties than their role as statistical units. For example, historical county jurisdictions are crucial in any effort to find records of past events in the archives of modern counties and to spotting signs of deeper historical developments in the society, politics, or economy of the state or locale. Moving beyond quantitative analysis expands the historian's focus to include phenomena that are rare or non-existent today, such as non-county areas, precursors of the states, and attachments of unorganized counties and non-county areas to operational counties. Attachments, in particular, were a vital feature in the evolution of jurisdiction and can be especially important in any search for the records of events that occurred where county jurisdiction has changed. This paper will describe these three elements of historical jurisdiction, explain how they relate to the better known boundary lines, and suggest how they may be analyzed and displayed in a GIS.

Related URL:
Atlas of Historical Couny Boundaries: AHCBP

International Workshop on Historical GIS Fudan University, Shanghai, August 23-25, 2001