County Composition of All Metropolitan Areas: 1900-2006
This set of tables shows all areas defined as metropolitan in the 2000 Census and traces their county composition back to 1900. Data is included on the 1900-1950 and 1970-2000 Censuses. Additional information is provided on the 2005 and 2006 ACS, where the lowest level of geography was the PUMA, which had the exact same boundaries as the 2000 PUMA Census data. Because the Census Bureau has not released information associating these PUMA boundaries with the 2005 and 2006 metropolitan area definitions, the 2005 and 2006 ACS versions of METAREA present metropolitan classifications based on metropolitan boundaries from 2000. The 2005 and 2006 METAREA county compositions are therefore consistent with the 2000 METAREA county compositions. For the pre-1950 years, definitions similar to those used in 1950 have been applied (see also the variable METAREA).
A companion set of tables are located through the following link: County Composition of Nineteenth Century Metropolitan Areas, 1850-2006; they show all areas defined as metropolitan in 1900 and trace changes in county composition from 1850 to 2006, including the 1850-1950 and 1970-2000 Censuses and the 2005 and 2006 ACS. Some metro areas are included in both tables. Users are advised to check the city-specific notes at the end of each table.