City directories, the precursor to the telephone book, are an invaluable resource for understanding the history of a city's businesses, organizations, and residents. Temple University maintains an excellent guide for understanding the use of city directories in research.
Penn's holdings of Philadelphia city directories can be found in Franklin by searching "Philadelphia (Pa) Directories" as a subject, or in our microfilm collection. First consult an index of the microfilm directories, City directories of the United States, 1860-1901: guide to the microfilm collection, available in the Van Pelt Reference Stacks at Z5771.2 .C58 1983. Directories are listed alphabetically by city. For Philadelphia, city directories include Boyd's, Gopsill's, McElroy's, as well as Macpherson's directory of 1785, the first American city directory. Each listing will tell you where to locate that directory in the microfilm, which is located in the Van Pelt Microtext Center. 1st Floor, Van Pelt Library.
Early (1785-1865) directories of Philadelphia are available online via the Internet Archive.
Ancestry.com is a useful tool for accessing census schedules. Unfortunately for researchers of cities, it was designed primarily for genealogists, and therefore is much easier to search by name of resident rather than location of residence. In order to research your neighborhood of interest:
The Philadelphia Social History Project (PSHP), directed by Theodore Hershberg at the University of Pennsylvania, was a pioneering effort by an interdisciplinary group of scholars and students to study the historic social, economic, and demographic dynamics of Philadelphia.
Book-length biographies can be found in Franklin by searching for a name as a Subject (e.g. Eakins, Thomas 1844-1916), or by searching the place or occupation plus Biography as a subject (e.g. Physicians Pennsylvania Philadelphia Biography). Other sources of biographies of Philadelphians are listed below.
Penn Libraries provides access, though the City of Philadelphia, to ownership records of individual parcels in the city. To access both current and historical records, you must use two different tools, DOR Parcel Explorer and Philadox.
The Sanborn Map Company helped fire insurance companies set rates in the late 19th and early 20th centuries with these detailed maps of each built structure, its use, dimensions, height, building material, and other relevant features (fire alarms, water mains and hydrants, for example).
Philadelphia neighborhoods are fluid entities without fixed boundaries. The resources below describe commonly accepted neighborhood boundaries. (For demographic or other data on neighborhoods, see Social & Cultural.)