The following is a list (by population) of all Metropolitan Statistical Areas as defined by the United States Census Bureau. Population estimates are current as of July 1, 2004. Metropolitan Statistical Area names are current as of December 1, 2005. In the United States, the Office of Management and Budget (OMB) has produced a formal definition of metropolitan areas. ... The United States Census Bureau (officially Bureau of the Census) is a part of the United States Department of Commerce. ... July 1 is the 182nd day of the year (183rd in leap years) in the Gregorian Calendar, with 183 days remaining. ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... December 1 is the 335th (in leap years the 336th) day of the year in the Gregorian calendar. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ...

It should be noted that more inclusive definitions of "metropolitan area" were used in the 1990's, such as "San Francisco-Oakland-San Jose" and "Washington-Baltimore". A more restrictive definition of metropolitan area used after the 2000 census resulted in breaking up these conglomerates or CMSA's (Consolidated Metropolitan Statistical Areas). Several major alterations were made to the Los Angeles, New York, Boston, Detroit, Philadelphia, and Cleveland areas as well, resulting in a more restrictive definition and thus a lower-ranked or lower total population. For example, Los Angeles-San Bernardino-Riverside would today be over 17 million, instead of just 12 million.

Several of these areas extend into Canada or Mexico but are not recognized by the US Census Bureau; population figures do not include sections of cross-border metropolitan areas outside of the United States.