Depending on what part of Ontario you are mailing to, the postal code varies. Postal codes in Canada are made up of a combination of three letters and three numbers in the format of letter-number-letter number-letter-number. For example, P9N 4A1 is a postal code in Kenora in Northern Ontario.
The province of Ontario is grouped into four regions: Eastern, Central, Southwestern, and Northern Ontario.
Each region can be identified by the letter a postal code starts with: Postal codes in Eastern Ontario begin with K, such as K8P 2E3, whereas postal codes in Central Ontario begin with L, such as L2A 6RB. Postal codes in Southwestern Ontario begin with N, and those in Northern Ontario begin with P.
For personal and limited business use, postal codes for a specific address can be looked up at Canadapost.ca. In addition, Canada Post provides a reverse lookup tool where you can find the address that matches a specific postal code. Rural addresses can begin with rural route (RR), post office box (PO Box), or general delivery (GD).
For frequent postal code searches from one computer, access to the tool might become restricted and Canada Post has to be contacted to regain access to the lookup tools.