A postal code (known in various countries as a post code , postcode , or ZIP code ) is a series of and/or digits appended to a postal address for the purpose of sorting mail.
There was a plan to introduce postal codes in Jamaica. On February 12, 2007 it was announced: "POST CODE PROJECT SUSPENDED INDEFINITELY"

The codes were planned to be alphanumeric, in the format: JMAPPNN, where

• JM is the ISO 3166-1 alpha-2 country code

• A is a letter for one of four zones

• PP are two letters for a parish.

• NN is a two digit number for a post office

   St. Mary codes List here