Only the first three characters are listed, corresponding to the Forward Sortation Area (FSA).
Canada Post provides a free postal code look-up tool on its website,[1] via its mobile apps for such smartphones as the iPhone and BlackBerry,[2] and sells hard-copy directories and CD-ROMs.
Many vendors also sell validation tools, which allow customers to properly match addresses and postal codes.
Hard-copy directories can also be consulted in all post offices, and some libraries.
H0M is an arbitrary FSA assignment, over 100 km from the centre of Montreal, as is H0H (representing the North Pole).