URBS 417: Cities and Sustainability: Defining Neighborhoods

A neighborhood is a fluid concept that is not necessarily neatly defined. When looking for information on a neighborhood, keep in mind the various ways of subdividing the geography of a city:

• Socially
  Neighborhoods like "Center City" or "Powelton Village" have boundaries according to common perception, that may vary depending on whom you ask.
• Administratively
  A division based on who is served by an organization. Could be a police district, a ZIP code, or the service area of a non-profit.
• Politically
  Philadelphia is divided into wards.
• Statistically
  The U.S. Census Bureau defines census tracts, block groups, and blocks for purposes of data collection.

Census tracts are "relatively permanent statistical subdivisions of a county…population size between 1,200 and 8,000 people, with an optimum size of 4,000 people":

Block groups are “generally defined to contain between 600 and 3,000 people”:

Census blocks are the smallest census geographies. In some cases, they have no population at all: