ISO 3166-3:2020

Overview

ISO 3166-3:2020 - "Codes for the representation of names of countries and their subdivisions - Part 3: Code for formerly used names of countries" is the third-edition (2020) ISO standard that specifies guidelines for implementing and maintaining codes for formerly used country names. It covers non-current country names removed from ISO 3166 since the first publication in 1974 and provides a structured, database-oriented approach for traceability of historical country codes.

Key facts:

• Edition: Third (2020)
• Purpose: Represent deleted/non-current country names
• Format: Standard described as a database; codes accessible via ISO’s Online Browsing Platform (OBP)
• Encoding: UTF-8 (ISO/IEC 10646)

Key topics and requirements

ISO 3166-3 defines the principles, structure and maintenance rules for formerly used country codes, including:

• Principles for inclusion - criteria that qualify a removed country name for listing (see change of country name, division, merger, obsolescence, change of alpha-2 status).
• Code elements - use of existing code types (alpha-2, alpha-3, num-3) and a specific alpha-4 construct for formerly used names (original alpha-2 + two letters, with meaning tied to the cause of change).
• Periods of validity & traceability - dates for start/end of validity and explicit status of alpha-2 code elements (assigned, unassigned, reserved transitional/exceptional/indeterminate).
• Maintenance rules - role of the ISO 3166 Maintenance Agency (ISO 3166/MA), database paradigm for updates, and a decoding table to interpret historical changes.
• Data quality - standardized character handling (diacritics checked against ISO/IEC 10646) and consistent use of descriptors rather than column positions.

Applications

ISO 3166-3 provides practical value for any system or workflow that must interpret, store, migrate or display historical geopolitical data:

• Archival and historical databases that preserve legacy country identifiers
• Government, customs, postal and legal records where historical country status matters
• Finance, insurance and trade systems reconciling legacy transaction records
• GIS, statistical and demographic datasets requiring consistent historical coding
• Libraries, publishers and researchers managing bibliographic and historical references
• Software and data integrators implementing backwards-compatible country-code mappings

Who uses this standard

• ISO 3166/MA and national standards bodies
• Data architects, developers and database administrators
• Customs, postal operators, IATA, WCO and other international organizations
• Archivists, statisticians, historians and legal professionals

Related standards

• ISO 3166-1 (current country codes)
• ISO 3166-2 (subdivision codes)
• ISO/IEC 10646 (Universal Character Set)
• ISO 15924 (scripts)
• ISO/IEC Directives (maintenance & editorial rules)

Using ISO 3166-3 helps ensure consistent, auditable handling of historical country names and supports interoperable, language-independent archival and data-exchange workflows.