Historical Census Research  Tags: census congress government_information history united_states census  

Census geographic levels have changed over time, a good source for historical background is:

• Geographic Areas Reference Manual: GIC C.6/2: G29/4 (available online or in print)

The diagram below illustrates the legal and statistical entities for which the Census Bureau currently tabulates data during the decennial census. Definitions of these areas can be found here.

[Source: U.S. Census Bureau, Geography Division]

The Davidson Library has tract and block maps from their first printing in 1940.  Pre-1990 census maps, and 1990 tract maps, frequently were bound in, or shelved with Census volumes.

1990 block maps:

• Santa Barbara, San Luis Obispo, Ventura counties: GIC C3.224/5:90-1-6-79X/PT.1-2
• Los Angeles, Orange, San Diego, San Francisco, San Luis Obispo, Santa Barbara, Ventura counties: Map & Imagery Lab

2000 block maps:

• Santa Barbara County only: GIC C3.224/5:PHC 2000-1-6-75/MAPS
• Los Angeles, Orange, San Diego, San Francisco, San Luis Obispo, Santa Barbara, Ventura counties: Map & Imagery Lab

2000 tract maps:

• American FactFinder
• California only: GIC: C3.223/11:2000/06/COUNTYNOX/MAPS