There are several ways you can find demographic census data, depending on the timeframe you are researching.
Census of Population and Housing Print Documents (and Electronic Surrogates)
Data for the years 1970, 1980, and 1990 can be found in the print volumes located on the First Level Mezzanine in the Library, or via the link to the electronic versions. Some tips for using these files:
- If you are using the electronic versions, note that the California volumes encompass multiple large files that you will need to download. The sections are labeled slightly differently from year to year, but as a general rule you want to look for sections that report on "Characteristics of the Population."
- Look at the table of contents for the volume - this will give you a listing of the tables that are included in it. Keep in mind that most Census tables are arranged by geographical size - from largest size to smaller sizes. For example, a table may first contain state level data; then county level; then cities over 250,000; then smaller areas of population.
- If you are using one of the ZIP file downloads, always open the first document in the folder - this should provide a linked table of contents that will allow you to jump quickly to other sections of all the PDFs in the folder. (Note: you can go back to the main document by clicking on the top level "Table of Contents" link in the PDF.)
- If you are trying to do an analysis at a smaller level of geography than city/town level, there are Census publications that cover census tracts for many major cities. These publications are shelved in the Government Documents collection on the First Level Mezzanine in the Library. I strongly suggest making an appointment with me if you want to explore the census tract level data.
National Historical Geographical Information System (NHGIS)
NHGIS is an online resource for extracting and downloading data from censuses back to 1790. You can also download GIS boundary files via this system. Please note that not all census data has been made available through this system. To download data from NHGIS, you will need to create an account (this is a free service).
- To search for data, click on "Select Data" from the left hand side menu.
- Use the filters to determine your data selection.
- When you've found a data set that you want to download, click the yellow plus next to the data set's title. This will add the data set to your data cart.
- Click "continue" to proceed to your data cart and initiate the download process.
- Please note the download process is not instantaneous - your request will be queued and its progress recorded on the downloads page (hit refresh to see status progress). You will also receive an email when the download is ready.
- Your data download will include one or more CSV files and a codebook for each CSV file. Use the codebook to determine what variable each column on the CSV file corresponds to.
- Also note that the NHGIS downloads are generally for the entire country - so you will have to find the appropriate geographies in California on the spreadsheet and delete the other data (a data clean-up measure, if you will).
American FactFinder is the Census Bureau's online tool for finding data from the Census since the year 2000. Use the advanced search to select your topic, year, and geographies for data tables. These tables can be downloaded in Excel or CSV formats.