For every country and territory in the world that the United States officially recognizes, the United States Postal Service (USPS) assigns it a unique two-letter abbreviation. The two-letter abbreviations are always written in uppercase letters.
Canadian States and Territories
Canada consists of 13 states and territories. The following is a complete list of the states and territories along with their official USPS abbreviations: Alberta (AB), British Columbia (BC), Manitoba (MB), New Brunswick (NB), Newfoundland and Labrador (NL), Northwest Territory (NT), Nova Scotia (NS), Nunavut (NU), Ontario (ON), Prince Edward Island (PE), Quebec (QC), Saskatchewan (SK) and Yukon Territory (YT).
Mexican States and Territories
Mexico consists of 32 states and territories. The following is a complete list of the states and territories and their official abbreviations: Aguascalientes (AG); Baja, California North Territory (BA); Baja, California South Territory (BJ); Campeche (CE); Chiapas (CI); Chihuahua (CH); Coahuila de Zaragoza (CU); Colima (CL); Destrito Federal (DF); Durango (DO); Guanajuato (GX); Guerrero (GR); Hidalgo (HL); Jalisco (JL); Estado de Mexico (MX); Michoacande Ocampa (MC); Morelos (MR); Nayarit (NA); Neuvo Leon (NN); Oaxaca (OA); Puebla (PB); Queretaro de Arteaga (QU); Quintana Roo (QR); San Luis Potosi (SL); Sinaloa (SI); Sonora (SO); Tabasco (TB); Tamaulipas (TA); Tlaxcala (TL); Veracruz-Llave (VC); Yucatan (YU); and Zacatecas (ZA).
Other Countries and Territories
The following is a partial list of other countries and territories and their official U.S. abbreviations: Afghanistan (AF), Argentina (AR), Brazil (BR), British Virgin Islands (VI), Cambodia (CB), China, Mainland (CH), England (UK), Ghana (GH), Haiti (HA), Iraq (IZ), Italy (IT), Pakistan (PK), Russia (RS), South Africa (SF), Switzerland (SZ) and United Arab Emirates (AE).
Addressing International Mail
According to the USPS, address international mail using the full name of the destination country, not the two-letter abbreviation. Clearly write the country in English using uppercase letters on the last line of the destination address. The USPS also recommends writing the entire destination address in uppercase letters. For example:
MS JOYCE BROWNING 2045 ROYAL ROAD 06570 ST PAUL France