Postal codes in Cygnia, colloquially known as postcodes, are five to seven-character strings that form part of a postal address. Cygnian postcodes are alphanumeric, and are in the format A(A)1(1) 111, where A is a letter and 1 is a digit, with a space separating the last three digits from the other characters. There are over 800,000 postcodes currently in service across Cygnia using postal districts ranging from SW1 in Northam, TS to E11 in New Caledonia.
A postal district is a geographic area in which all postcodes start with the same three or four characters. The first letter(s) of a postal district code denotes a particular "postal region". Most states are divided into several regions (some smaller states are served by a unified "at-large" postal region). The regions were originally created by the Imperial Postal Service to serve a roughly equal number of people, although population growth and demographic change means this is in some areas no longer the case. After the letters, the final number denotes the district itself, which is a division of a postal region.