ISO 3166-2:2020

Overview

ISO 3166-2:2020 defines the rules and guidelines for creating and maintaining country subdivision codes - the standardized codes that represent principal administrative divisions (states, provinces, regions, etc.) of countries listed in ISO 3166‑1. This fourth edition formalizes the shift to a database-centric model, aligns character usage with ISO/IEC 10646 (Unicode), and uses UTF-8 encoding for consistent, international data exchange. The code format is specified (see Key Topics).

Key Topics

• Scope and purpose: Provides basic guidelines for implementation and maintenance of current country subdivision names in coded form for any application requiring coded subdivisions.
• Code structure: Country subdivision code elements are composed of an alpha‑2 country code, a hyphen-minus, then up to 3 characters (A–Z, 0–9) - maximum length 6 characters in total.
• Language and scripts: Guidance on choice of language, romanization systems and character sets; references to ISO 639 language codes and ISO 15924 script codes are included.
• Data model and database: Codes and descriptive text moved to a single database paradigm; ISO Online Browsing Platform (ISO OBP) is the public interface for the code data.
• Maintenance and governance: Updates and stewardship are managed by the ISO 3166 Maintenance Agency (ISO 3166/MA) with procedures for name changes, code alterations, reservations and change tracking.
• Interoperability: Principles for relating subdivision codes to national/international coding systems and for ensuring one‑to‑one correspondence between names and code elements.
• Character consistency: All characters (including diacritics) checked against Unicode (ISO/IEC 10646) for consistent usage.

Applications

ISO 3166-2:2020 is used wherever standardized representation of administrative areas is needed:

• Data exchange and integration between government agencies and international organizations
• Addressing, postal services, customs and trade declarations
• Geographic Information Systems (GIS) and mapping services
• Business analytics, reporting and statistical aggregation
• E‑commerce, logistics and supply‑chain management
• Database design and APIs requiring reliable subdivision identifiers

Who uses this standard

• IT architects, database designers and developers
• National standards bodies and government administrations
• International organizations, customs and postal operators
• GIS professionals, statisticians and data analysts
• Software vendors and e‑commerce platforms

Related Standards

• ISO 3166‑1 (country codes)
• ISO 3166‑3 (codes for formerly used country names)
• ISO 639 (language codes)
• ISO/IEC 10646 (Universal Coded Character Set / Unicode)
• ISO 15924 (script codes)

Using ISO 3166‑2:2020 ensures consistent, interoperable subdivision identifiers across systems, languages and borders - essential for reliable international data exchange and geographic referencing.