The 2010 Universe of Cities

Using a number of data sources, scholars at New York University and the University of Connecticut, in partnership with UN-Habitat and the Lincoln Institute of Land Policy, and in collaboration with the UN Population Division, have identified the universe of all 4,231 cities and metropolitan areas that had 100,000 people or more in 2010. All these cities have identifiable, freestanding, contiguous urban extents, and all of these cities have names, coordinates, and population figures associated with them from three time periods: 1990, 2000, and 2010. This paper introduces this universe of cities and presents a number of new findings: (1) the population sizes of the universe of cities did not follow the regularities of Zipf’s Law or Gibrat’s Law completely; (2) the numbers of large and small cities grew proportionately to the total number of cities in the universes of cities; and (3) the variations of city population size among regions were distinguishing but dwindled over time. We present our findings from two perspectives: the trends and distributions of city population sizes, and of city population growth rates. This new universe of cities lays the foundation for a new perspective on global urbanization that focuses on cities as units of analysis, rather than on countries.