ICR 110

ICR 110 is the International Codes Registry standard for administrative subdivision identifiers.

ICR 110 identifies first-level and selected lower-level administrative divisions. Each code begins with the parent ICR 100 territory code, followed by a hyphen and a stable subdivision element.

Examples:

NL-ZH
RO-B
RO-IF

The subdivision element may contain one to three letters or digits. Existing national abbreviations may be retained when they are stable and do not conflict within the parent territory.