How were the geographic boundaries of a city defined?
The geographic boundaries of a city are defined using the guidelines established for Metropolitan Statistical Areas (MSAs) by the federal agency the Office of Management and Budget (OMB). OMB publishes a comprehensive definition of MSA boundaries every 10 years to reflect population changes documented by the decennial Census. In order for an area to be designated an MSA, the area has to have at least one urbanized area of 50,000 or more in population, plus adjacent territory that has a high degree of social and economic integration with the urban core as measured by commuting ties.
