ISO 3166-2 Subdivision Codes — States, Provinces, and Regions

What Is ISO 3166-2?

While ISO 3166-1 covers countries, ISO 3166-2 defines codes for the principal subdivisions of each country — states, provinces, territories, regions, departments, and other administrative divisions.

Code Format

ISO 3166-2 codes follow the pattern:

[Country Alpha-2]-[Subdivision Code]

The subdivision part varies in length and format by country:

Country	Format	Examples
US	US-XX (2 letters)	US-CA, US-NY, US-TX
Canada	CA-XX (2 letters)	CA-ON, CA-BC, CA-QC
UK	GB-XXX (3 letters)	GB-ENG, GB-SCT, GB-WLS
Japan	JP-XX (2 digits)	JP-13 (Tokyo), JP-27 (Osaka)
Germany	DE-XX (2 letters)	DE-BY (Bavaria), DE-BE (Berlin)
Australia	AU-XXX (2-3 letters)	AU-NSW, AU-VIC, AU-QLD
France	FR-XX (2 chars)	FR-75 (Paris), FR-13 (Bouches-du-Rhone)
India	IN-XX (2 letters)	IN-MH (Maharashtra), IN-KA (Karnataka)

Common US State Codes

US-AL Alabama      US-IL Illinois     US-MT Montana      US-RI Rhode Island
US-AK Alaska       US-IN Indiana      US-NE Nebraska     US-SC South Carolina
US-AZ Arizona      US-IA Iowa         US-NV Nevada       US-SD South Dakota
US-AR Arkansas     US-KS Kansas       US-NH New Hampshire US-TN Tennessee
US-CA California   US-KY Kentucky     US-NJ New Jersey   US-TX Texas
US-CO Colorado     US-LA Louisiana    US-NM New Mexico   US-UT Utah
US-CT Connecticut  US-ME Maine        US-NY New York     US-VT Vermont
US-DE Delaware     US-MD Maryland     US-NC North Carolina US-VA Virginia
US-FL Florida      US-MA Massachusetts US-ND North Dakota US-WA Washington
US-GA Georgia      US-MI Michigan     US-OH Ohio         US-WI Wisconsin
US-HI Hawaii       US-MN Minnesota    US-OK Oklahoma     US-WY Wyoming
US-ID Idaho        US-MS Mississippi  US-OR Oregon

Use Cases in Software

1. Address forms — State/province dropdowns keyed by ISO 3166-2 codes
2. Tax calculation — US sales tax varies by state (US-CA has different rates than US-OR)
3. Shipping zones — Delivery cost depends on the subdivision
4. Regulatory compliance — GDPR applies differently across EU member state subdivisions
5. Localized content — Show region-specific offers or pricing

Relationship to ISO 3166-1

ISO 3166-2 depends on ISO 3166-1 — the country code prefix is always the alpha-2 code. If a country's alpha-2 code changes, all its subdivision codes update accordingly.