Feb 19 -- The Census Bureau invites public comments by May 20, 2021 on its proposed criteria for defining urban areas based on the results of the 2020 Decennial Census. The Census Bureau delineates urban areas after each decennial census by applying specified criteria to decennial census and other data. Since the 1950 Census, the Census Bureau has reviewed and revised these criteria, as necessary, for each decennial census in order to improve the classification of urban areas by taking advantage of newly available data and advancements in geographic information processing technology.
FR notice describing proposed criteria and inviting comments: https://www.federalregister.gov/documents/2021/02/19/2021-03412/urban-areas-for-the-2020-census-proposed-criteria
The Census Bureau's urban area classification is fundamentally a delineation of geographical areas, identifying individual urban areas as well as the rural portion of the nation. The Census Bureau's urban areas represent densely developed territory, and encompass residential, commercial, and other non-residential urban land uses. The boundaries of the urban areas have been defined primarily by using measures based on population counts and residential population density, and also by using measures based on criteria that account for non-residential urban land uses, such as commercial, industrial, transportation, and open space that are part of the urban landscape. Since the 1950 Census, when the Census Bureau first defined densely settled urbanized areas of 50,000 or more people, the urban area delineation process has addressed non-residential urban land uses through criteria designed to account for commercial enclaves, special land uses such as airports, and densely developed noncontiguous territory.
The Census Bureau adopted six substantial changes to its urban area criteria for the 2000 Census:
Defining urban clusters using the same criteria as urbanized areas.
Disregarding incorporated place and census designated place (CDP) boundaries when defining urbanized areas and urban clusters.
Adoption of 500 persons per square mile (ppsm) as the minimum density criterion for recognizing some types of urban territory.
An increase in the maximum jump distance for linking densely developed territory separated from the main body of the urban area by intervening low density territory from 1.5 to 2.5 miles. This recognized the prospect that larger clusters of non-residential urban uses might offset contiguity of densely settled territory.
Introduction of the hop concept to provide an objective basis for recognizing that nonresidential urban uses, such as small commercial areas or parks, create small gaps between densely settled residential territories, but are part of the pattern of urbanization.
Adoption of a zero-based approach to defining urban areas.