u.s. Census Data
Archived by county. Within each county directory a zip directory contains archives for each data layer. In addition, a zip archive containing TIGER data for that county is included under the name zip.
The data are provided in ESRI Shapefile format and are presented in Geographic coordinates. The first few characters of the file name form a prefix that identifies the layer. The following chart decodes these prefixes:
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|---|
| blk | Census Blocks - 1990 | colblk | Census 2000 Collection Blocks |
| blk00 | Census Blocks - 2000 | wat2 | Water Polygons - multi |
| plc | Designated Places 1990 | lkA | Line features - Roads |
| plc00 | Designated Places 2000 | lkB | Line features - Rails |
| ccd00 | County Census Divisions 2000 | lkC | Line features - Misc. Trans. |
| vot00 | Voting Districts 2000 | lkD | Line features - Landmarks |
| kgl | Key Geographic Locations | lkE | Line features - Physical |
| lpy | Landmark Polygons | lkF | Line features - Non-visible |
| lpt | Landmark Points | lkH | Line features - Hydrography |
| taz | Traffic Analysis Zones | cty | County 1990 |
| elm | School Districts-Elementary | cty00 | County - Current |
| uni | School Districts-Unified | trt | Census Tracts 1990 |
| wat | Water Polygons | trt00 | Census Tracts 2000 |
| cd106 | Congressional Districts-106th | grp | Block Groups 1990 |
| cdc | Congressional Districts-Current | gr00 | Block Groups 2000 |
| lpy3 | Landmark Polygons - multi | Census Table Data |
http://www.census.gov/geo/maps-data/data/gazetteer.html
http://www2.census.gov/Econ2001_And_Earlier/CBP_CSV/
American Community Survey Data Users Group
DataShine Census Census mapped with context (Using ONS Quick Statistics data for England & Wales)