Creating Spaces for Historical Data Michael Ratcliffe Geographic Standards and Criteria Branch Geography Division US Census Bureau

2 Research Problem Baltimore Ecosystem Study researchers needed historical demographic data for areas in which they were collecting data about the physical environment over a 200 year period.

3 Challenges for researchers Obtaining historical demographic data at suitable geographic scales, particularly for small geographic areas; Developing a framework of small geographic areas for analysis of population distribution and demographic change over time; Relating historical demographic data to environmental and other information.

4 19 th Century Census Geography Counties Minor civil divisions Incorporated places Wards Enumeration districts Sanitary districts

5 Sources of Historical Geographic Area and Demographic Information Decennial Census Manuscript Forms –Header on each form has space to list state, county, county subdivision, and post office City and County Atlases –G.M. Hopkins, 1870s –Hexamer and Locher, 1860s and 1870s Fire Insurance Maps –Sanborn and Company –Hexamer, Ernest, and Son

6 G.M. Hopkins, Baltimore County Atlas, 1876

7 Source: S. Hinman, 2002

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9 Methodological Approaches Digitize geographic entity boundaries from historical maps Build a spatial framework using current census geographic areas

10 Reisterstown Census Tracts

11 Census Tracts and 1870s Reisterstown Tract Tract Tract

12 Population by Sex and Race Upper Gwynn’s Falls Watershed, 1870

13 Age and Sex Upper Gwynn’s Falls: 1870

14 Value of Personal and Real Property Upper Gwynn’s Falls, 1870

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17 (source: S. Hinman, 2002)

18 (source: S. Hinman, 2002)