Home > Data Services > Catalog . Restricted Data . Census . ACS

Search Data Services

Meta Search
search across all the following databases:

Data Catalog
Data and documentation

Common questions and answers.

Entire collection of data resources.

Latest Data News

RSS Feed icon

Health ABC data available through NIA website

More apportionment fun

Great Tweetstorm: Most important year in Economics?

Risk Visualization Theater

Missing girls in China maybe weren’t missing after all

Data Services Knowledge Base


What’s the difference between a PMSA and an MSA?


Metropolitan Statistical Areas (MSA) are one or more counties that contain a city of 50,000 or more, whereas Primary Metropolitan Statistical Areas (PMSA) are subareas that meet the qualification to be an MSA, but have a population of one million or more. PMSAs are always part of a Consolidated Metropolitan Statistical Area (CMSA).

Here is a link to the metropolitan areas at the time of the 2000 Census:


The Detroit-Ann Arbor-Flint CMSA (2162) is comprised of the Ann Arbor PMSA (0440), the Detroit PMSA (2160) and the Flint PMSA ( 2640).

Dothan, Alabama (2180) is an example of an MSA.

Note that the metropolitan area definitions have changed since the 2000 Census. The new definitions (December 2009) are:


A good starting point is:


This link allows you to look at the definitions on selected dates for many different geographies. It will always include the latest standard.

Annotated Resources:

Direct Links:

Related Question Groups: