The locale"s country identifier is also specified by an ISO standard, ISO 3166, which describes valid two-letter codes for all countries. ISO 3166 defines these codes in uppercase letters. The following table lists some commonly used country codes.

Country Code  Country
US United States
FR France
IE Ireland
CA Canada
MX Mexico

The country code provides more contextual information for a locale and affects a language's usage, word spelling, and collation rules.