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Research Guides

Finding Census Data

Most government material, including census statistical volumes, is housed in Government Publications  on the ground floor of Suzzallo Library. Librarians there can help you find material you need.

The UW Libraries subscribes to the academic version of The database is a major source for genealogical records including census, military, immigration, marriage, birth and other material. It also includes a growing number of articles and images related to family history such as yearbooks and biographical dictionaries. The academic version of does not include some portions of the personal subscription version such as the ability to create a family tree.

The database is primarily searched by name as users seek to find information about their ancestors. The latest census information dates from 1940.  Information collected by census takers includes names, ages, and relationships of all people in the household, country of origin, native language, information about home ownership, and other information varying by year.

Census Data as Historical Evidence

The census is a decennial (every 10 year) count of all people and households in the country. Information gathered during the census can include race, income, education level and more for a state, city and down to a census tract level (an area composed of approximately 1200 to 8000 people). 


  • The census reveals population trends over time. 
  • The census reveals socio-economic and housing information for an area.

Keep in mind

  • The census is a snapshot in time. Information is available for 2010 so changes since then are not reflected in the census data. The annual American Community Survey, which started in 2005, contains many statistics that once appeared in the decennial census.
  • Overtime the census gathered different sorts of information so it may not be easy to directly compare census data over time. For example if you are interested in Filipinos living in the International District in 1920 you will not be able to know because the census grouped most Asians under the racial category "other."
  • Actual household information is only available through the 1940 census because of privacy concerns so you cannot see who lived in a specific block in 1960.

How to Use Census Data

"The Federal censuses are an invaluable tool for historians and other social scientists... Despite their value, the census counts are nevertheless far from perfect. Like any historical source, they must be evaluated, their strengths noted, and their limitations recognized."

Printed copies of the statistical census volumes are housed in the Government Publications Section on the ground floor of Suzzallo Library.

For more information on using census data see: Making Sense of NumbersCensus DataMeasuring America: The Decennial Censuses from 1790 to 2000 & How to Use the Census Bureau's American Community Survey Like a Pro.