Population and Census Data

2010 Census population map of Cambridge

The majority of demographic information available about Cambridge derives from one of the U. S. Census Bureau programs. 

Links to Data

Demographic Information about Cambridge is available at three geographic levels:

Citywide Demographics 

Neighborhood Demographics, which provide information about the 13 neighborhoods of Cambridge

Census Tract Demographics, which provides information at the level of the census tracts used by the Census Bureau.  There are currently 32 census tracts in Cambridge.  Prior to 2010 there were 30 tracts.

U. S. Census Bureau Demographic Programs

Decennial Census

The Decennial Census, held once every ten years, provides basic population and household data. Questions cover the topics of sex, age, race, Hispanic origin, household relationship and housing tenure. As a true census, these questions are posed to every person resident in the United States at the date of the census, which has been April 1 for the past several iterations.

Up through 2000 the Decennial Census also included a "long form" component", which sampled one in six persons asking a wide variety of socioeconomic questions. The questions covered by the long form questionnaire were moved to new American Community Survey (ACS) in the following years.  As a result, the 2010 Decennial Census did not include any questions beyond the basic set asked of all participants.

Census Bureau 2010 Census Web Site 

American Community Survey

Following the 2000 Census, socioeconomic questions were moved from the Decennial Census "long form" questionnaire to the new American Community Survey (ACS). Unlike the Decennial Census, the ACS is an ongoing sample based survey. The Census Bureau designed the ACS to measure characteristics of a population but not the size of the population itself.

The ACS questionnaire is administered to a sample of households on an ongoing basis throughout the year.  In some cases this affects the comparability of results between the ACS and results from the Decennial Census prior to 2010. In other cases the wording of questions has changed placing limits on the comparability of data.  Please consult the ACS web site for the data set you are using to learn more about comparing ACS data to the Decennial Census and other ACS data sets.

Census Bureau American Community Survey Web Site

the ACS releases three sets of data tables every year. The data sets cover one, three and five year time spans.  The longer the time span the larger the sample size and the smaller the margin of statistical error found in the data.  Citywide information on the CDD web site usually uses data from the three year tables. Census tract and block group data is only found in the five year tables.

Population Estimates Program

The Population Estimates program produces estimates of the population for the years between decennial census activities.  Figures from the Estimates program serve as the basis for the population characteristics figures found in the ACS.  The Population Estimates program has a mixed history predicting population change in Cambridge.

Census Bureau Population Estimates Program Web Site

For More Information

For more information about socioeconomic and demographic statistics about Cambridge, please contact Cliff Cook, ccook@cambridgema.gov, Planning Information Manager, at 617/349-4656.