The census tract boundary maps for Los Angeles County have been down loaded from the U.S. Census Bureau web site for faster access. You will need Adobe Acrobat Reader installed on your computer to access them because they are in Portable Document Format (PDF). Adobe Acrobat Reader can be downloaded at no charge from Adobe.com.
How the Tract maps are arranged
Forty-one files correspond to a grid system for the county.
Start by opening the PDF file named "L A County Tracts Master Grid"
Zoom into the desired area and make a note of the grid coordinates: for example D14
Select the needed file. The grid letter and number are at the end of the file name.
Open up the file(s) and zoom in until you can read the tract number and street names. Make a note of the geographical area in question.
To Retrieve Census Data for Tract Numbers
Go to the US Census Bureau and select American FactFinder. Click on "Enter a Street Address" (upper left hand corner). You will be able to select a map showing the area of your census tract and surrounding ones and all data tables with information about your census tract.
Select the Data Set needed
2000 Summary File 1 contains the 100% data collected on the Short Form.
2000 Summary File 3 contains the sample data collected on the Long Form.
Select Detailed Tables or Quick Tables
In the "Geographic Type" box select Census Tract.
In the "Select a State" box select California.
In the "Select a County" box select Los Angeles.
The census tract numbers will load in the "Geographic area" box - be patient - there are over 1,800 tracts for Los Angeles County!
Using the tract numbers collected earlier from the tract maps, select them by clicking on them (more than one can be selected at a time), and then click on "Add".
Click on "Next" which will bring up a list of data tables.
Select the table(s) and click on "Add".
Note: the "What's this" feature is very useful. It will show a template of the data contained in each table.
"Show Table" will display the selected table(s) with the data for the selected census tracts.
If unsure as to what table you need, select the "Search" tab at the top. The census year (1990 or 2000), keyword and subject boxes can be used to do a search which will bring up a list of tables containing your search terms.
Census tracts are made up of Block Groups, and Blocks. If census data is needed for even smaller areas than tracts some of it is available down to the Block level. Summary File 3 data is only available down to the Block Group level. Boundary outline maps for Blocks are also available from the Bureau of the Census web site. Click on Maps in the Geographysection, Map Products, and Census Geography. Block maps are arranged in a system similar to the Census Tract maps. Please be aware that Tract and Block maps change from census to census due to changes in population.