Old ZIP codes

The place file (posted 2014 Dec 25) contains 119,980 unique 49-character records in the following format:
Field Size
----- ----
ZIP   5    ZIP code
PLACE 28   Name associated with the ZIP
STATE 2    State where PLACE is located
FROM  6    Year-month (YYYYMM) the PLACE was first associated with the ZIP
TO    6    Year-month (YYYYMM) the PLACE was last associated with the ZIP
CR    1    Carriage return
LF    1    Line feed
For a given date range in a record, the PLACE as listed was associated with that ZIP code. Outside the date range either no data is available, or the PLACE or STATE fields changed as indicated by some other record, or the ZIP code was not assigned and no other record applies.

Data before October 1989 and after December 2014 are not available, so the proper content of records before and after those dates can't be reliably determined. WARNING: ZIP data changes monthly, and official ZIP records include additional important flags not listed here. Current and complete databases are here. WARNING: Determining the proper ZIP for a city, or vice versa, requires considering the address.

Records with Yellow (Y) dates are probably correct but may be wrong by a month or two. Green (G) dates are accurate. No data is available for Red (R) months, so they are never used as beginning or ending dates, and date ranges assume data did not change in those months.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1989 R R R R R R R R R Y R R
1990 R R R Y R R Y R R R Y R
1991 R R Y R R R Y R R Y R R
1992 Y R R Y R R Y R R Y R R
1993 Y R R Y R R Y R R Y R R
1994 G R R G R R G R R G R R
1995 G R R G R R G R R G R R
1996 G R R G R R G R R G R G
1997 R G R G R G G G G G G G
1998 G G G G G G G G R G G G
1999
to
2014
G G G G G G G G G G G G
The po file (posted 2014 Dec 25) contains 50,693 unique 49-character records in the following format, using the same date color codes as above:
Field Size
----- ----
ZIP   5    ZIP code
PO    28   Post office the ZIP belongs to
STATE 2    State where post office is located
FROM  6    Year-month (YYYYMM) the post office was first associated with the ZIP
TO    6    Year-month (YYYYMM) the post office was last associated with the ZIP
CR    1    Carriage return
LF    1    Line feed
You may sell, modify, and redistribute either file as you wish. However, you must prominently link to this page as the source of the data. For questions or comments contact us.