Geography is central to the work of the Census Bureau, providing the framework for survey design, sample selection, data collection, tabulation, and dissemination. Geography provides meaning and context to statistical data.
This diagram shows how the levels of geography relate from the National level down to Census Blocks.
The Geographic Areas Reference Manual (GARM) describes in great detail the basic geographic entities the Census Bureau used in its various data tabulations for the 1990 Census and documents the purposes, definitions, standards, criteria, and procedures used to select, define, delineate, and revise those geographic entities.
Geography reference maps show the boundaries and names (or other identifiers) of geographic areas for which the Census Bureau tabulates statistical data.