ZIP Code Information

In connection with my previous post on visualizing US ZIP codes, here are some links to ZIP code data.

From: http://www.sdc.ucsb.edu/holdings/zip_codes.txt

The Census Bureau has been providing ZIP Code area centroids which is probably the dataset used in the distance calculation routines. To overcome this mapping difficulty, the Census Bureau has created the ZIP Code Tabulation Area (ZCTA) by using aggregations of Census blocks. But they warn that there is no correlation between the US Postal Service ZIP Codes and the US Census Bureau-created geography of those ZIP Codes. Each of datasets should be used with full knowledge of their method of creation and intended uses.

US POSTAL SERVICE ZIP Code Lookup and Address Information page http://www.usps.com/ncsc/ziplookup/lookupmenu.htm

ZIP Code FAQ
http://www.usps.com/zip4/zipfaq.htm

ZIP Code lookup service
http://www.usps.com/zip4/welcome.htm

US CENSUS BUREAU ZIP Code information and FAQs http://www.census.gov/geo/www/tiger/tigermap.html#ZIP
http://www.census.gov/cgi-bin/geo/tigerfaq?Q16
http://www.census.gov/cgi-bin/geo/tigerfaq?Q17
http://www.census.gov/cgi-bin/geo/tigerfaq?Q18
http://www.census.gov/cgi-bin/geo/tigerfaq?Q19
http://www.census.gov/cgi-bin/geo/tigerfaq?Q20

Census 2000 U.S. Gazetteer Files
http://www.census.gov/tiger/tms/gazetteer/
http://www.census.gov/geo/www/gazetteer/places2k.html

ZIP Code Tabulation Areas
http://www.census.gov/geo/ZCTA/zcta.html
http://www.census.gov/prod/2001pubs/mso01zcta.pdf

2000 5-Digit ZIP Code Tabulation Areas
http://www.census.gov/geo/www/cob/z52000.html

2000 3-Digit ZIP Code Tabulation Areas
http://www.census.gov/geo/www/cob/z32000.html

Text file of ZIP Codes and centroids
http://www.census.gov/ftp/pub/tiger/tms/gazetteer/zips.txt http://www.census.gov/geo/www/gazetteer/newpagefiles/zip90r.txt

1990 ZIP Code file with lat/lon centroids
http://www.census.gov/geo/www/tiger/zip1999.zip

MISCELLANEOUS

Zip Codes are Not Areas! http://exchange.manifold.net/manifold/manuals/5_userman/mfd50Zip_Codes_are_Not_Areas.htm

As with most public domain data, there are many commercial enhancements and services created with specific uses of the data in mind. Here is just one such company:
http://www.zipdatafiles.com/data/