Social Explorer (easiest to use, choose "Data & Tools" then reports.)
Has the 1, 3 and 5 year annual datasets from 2006 forward.
Tables are listed both with SE numbers and names and with AFF numbers and names.
Includes only the Detailed Tables and not the profiles subject and quick tables.
ACS FTP site (expert users only)
Complete data from all ACS 1 year estimates files .
Tables in the ACS
Tables that start with the letter "B" are detailed tables on a specific topic.
Tables that start with the letter "C" are collapsed versions (fewer rows) of a "B" table.
Topics covered in table starting with "G" or "S" repeat information found in the "B" tables either for a specific geographic area and/or on a theme that combines topics.
The U.S. Gazetteer files provide a listing of all geographic areas for selected geographic area types. The files include geographic identifier codes, names, area measurements, and representative latitude and longitude coordinates.
The boundary files used by the ACS are those used with the Decennial Census.
Use the Tiger/Line Shape files choosing the most recent boundary files for ACS dates with a time span ending in 2010 or later and choosing the 2009 boundary files for ACS 2009 and earlier.
The exception to these rules is PUMA boundaries. The ACS 2010 uses 2000 PUMA boundaries.