Welcome to Temple's research guide for early Philadelphia city directories. The study of historical directories is a relatively new one, but one with great potential rewards.
City directories were compiled in "biographical" order-- by surname and first name-- for the purpose of finding any given person. They can of course still be used for that purpose, but if we put those directories in database format and rearrange their entries geographically, we can see the city the way the people of the past that we are studying did. In some sense we are recreating the city as it was, house by house and block by block.
The resulting field of study, termed "geohistory" by one of its earliest projects, the Philadelphia GeoHistory Project, offers enormous possibilities for scholars studying almost anything about the past-- neighborhoods, ethnicity, architecture, economics, genealogy and many others.
Geohistory is actually a pre-existing term. The International Encyclopedia of Human Geography gives this definition: "The term geohistory, coined by Braudel in 1949, designs a scientific approach which combines geography and history in order to show the role played by environmental constraints and human agency in shaping spatial organization." The form of geohistory which uses city directories, then, is a narrower, more specific kind of geohistory,
What geohistory offers, in essence, is an increased number of links between information. Directories have always provided links between individual people and individual places. In geohistory's application to directories, those links are integrated into something like the many aspects of life, interwoven as they are like threads with work and community. Social networks like those of neighbors, churches, fraternal and political organizations become easier to trace and study when the individual items from varying sources of data like censuses and newspapers are linked to one another through the physical location of the individuals and organizations involved.
Another term for directory-based geohistory is "historical GIS".