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Frequently Asked Questions


American FactFinder is an online application that provides access to detailed tables and maps for population, housing and businesses. These tables are manipulable, downloadable and printable.


You can start by checking out our Quick Start Guides, which are available on our Training Page. The US Census Bureau also provides a short introductory guide to using AFF.


The Census Bureau publishes an in-depth FAQ, which is available here. They also allow you to Chat or submit a question which they'll answer via email. You can also contact our office with any questions at dlg.helpdesk@state.co.us.


We do! Visit our Training page for more information. We offer in-person and webinar-based trainings. We also have recorded webinars you can view anytime.


There are multiple way to search by geography, and Quick Start is the easiest.


  • Start on the AFF main page (http://factfinder2.census.gov)
  • Quick Start is made up of two text boxes. In the text box on the left, type "Population" and in the text box on the right, type in the name of your city, town, county or state. Click GO to see a list of search results.
  • A box entitled "Community Facts" will appear above your search results. Here you will see various data you can view about your community. CLick on the first link under 2010 Census. This will open a table where you will find the population for your community.
  • You can also select a table name in the search results, located under "Community Facts". The search results will be organized by year starting with the most recent tables.


If you're interested in more advanced geography searches, please visit our Training Opportunities page.

  • Start at the AFF Search page
  • Click the blue Geographies button the lefthand side of the screen. The geography overlay will open. Make sure the List tab is selected, then choose either County of Place within state from the drop down list.
  • Select Colorado from the next drop down list, then choose All Counties Within Colorado from the list (it will be listed first), and click Add To Your Selections.
  • The chosen geography has been added to the Your Selections box. You can now close out of the geography overlay.
  • Start on the AFF Main page
  • Click on the blue Geographies box on the left side of your screen. The geographies overlay will open, choose the Name tab.
  • Under Geography Filter Options, click on Census Tract (you'll see it added to the Your Geography Filters box), then click on Within State to expand that category. Choose Colorado.
  • Click on Within Place, then click the name of the city or town you're searching for. Once you do, the census tracts within that Place will be listed in the Geography Results pane.
  • You can either check the box to the left of the All Census Tracts Within... table, or you can check the Check All box at the top, then click Add. The chosen tracts will be added to the Your Selections box.

The Base Tables, called Detailed Tables in the American Community Survey (ACS), contain all of the detailed data collected in the survey.


Depending on the selected geography, ACS detailed tables may be displayed in two versions. This variation in the base table display is designed to handle data filtering that is applied to the ACS results.


  • Differences
    • The "B" or base table displays the more detailed data.
    • The collapsed "C" table is very similar to the B table with teh same number (e.g., C07001 and B07001), but two or more lines from the B table have been collapsed to a single line in the C table. For example, the lines "75 to 79 years", "80 to 84 years" and "85 years and over" from a B table may be collapsed to a single line of "75 years and over" in a C table. Not every B table has a collapsed version.
  • Similarities
    • Both versions of the base tables can be accessed from the Detailed Tables path.
    • Both versions of the base tables will be listed together in pairs in the show all tables view on the Select Tables page.

Users are able to switch between the base table and the collapsed version table using a hyperlink displayed above the table result.


In AFF, you can build a map of a specific piece of data about a particular area. These maps are called thematic maps. You can create thematic maps from the table view of a product. Simply select the "Create a Map" button and follow the instructions to create your map.


Note that:

  • The data in some tables are not appropriate for mapping (for example, Data Profiles); and
  • You must select at least 2 like geographies (for example, 2 or mose state) to map.


For more information visit the Create a Map Tutorial.


AFF works best with Internet Explorer 7 and Mozilla Firefox 3.6.


ACS 5-year estimates are available down to the Block Group level, but not through American FactFinder. To access the BG data, you need to download the Summary File Retrieval Tool. It's available about halfway down the page, and right below that is a user guide.


A complete list is available within the ACS technical documentation for each set of estimates: 1-year, 3-year and 5-year.