The A1A 1A1 Structure
Introduced gradually between 1971 and 1974, the Canadian postal code is a six-character alphanumeric string in the format ANA NAN, where 'A' is a letter and 'N' is a number. This alternating structure was chosen to be easily readable by both human eyes and early optical character recognition (OCR) sorting machines.
Forward Sortation Area (FSA)
The first three characters form the Forward Sortation Area (FSA). The very first letter represents a specific province or major geographic region. For instance, 'M' represents Metropolitan Toronto, while 'V' stands for British Columbia. The number that follows indicates whether the area is urban or rural. A '0' means a vast rural region, while numbers 1-9 indicate urban centers.
Local Delivery Unit (LDU)
The last three characters form the Local Delivery Unit (LDU). This gets incredibly specific, identifying a single city block, a large apartment building, or even a specific rural community. It is so precise that Canada Post can sort mail into the exact order the postman will walk down the street!