This US state abbreviations reference lists all 50 states, the District of Columbia, and US territories with their official USPS two-letter codes, ISO 3166-2 identifiers, capital cities, and year of admission to the union. Search by state name or abbreviation to find any entry instantly.
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How to Use the US State Abbreviations Reference
This reference lists all 50 US states, the District of Columbia, and 6 territories with their official postal abbreviations. Use the search box to find any state instantly by name, abbreviation, or capital city.
USPS vs ISO Codes
The USPS code is the two-letter abbreviation used on mail addresses (e.g., CA for California). The ISO 3166-2 code is the international standard used in databases, software, and geographic systems — it adds a US- prefix (e.g., US-CA). Use USPS codes for mailing addresses; ISO codes for programming and international data exchange.
Common Confusing Abbreviations
MA = Massachusetts (not Maine — ME). MI = Michigan (not Mississippi — MS). MO = Missouri (not Montana — MT). MN = Minnesota. ME = Maine. The M-states are the most commonly confused abbreviations in US addresses.
Territories vs States
The US has 5 inhabited territories: Puerto Rico (PR), Guam (GU), US Virgin Islands (VI), American Samoa (AS), and Northern Mariana Islands (MP). Territories have USPS codes for mail routing but are not states. Territory residents are US citizens but cannot vote in presidential elections.
FAQ
Is this state abbreviations reference free?
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Is my data safe when using this tool?
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Why does Massachusetts use MA and not MS?
Mississippi was already assigned MS, and Maine was assigned ME. When the USPS standardized two-letter abbreviations in 1963, Massachusetts got MA. Before standardization, Massachusetts was sometimes abbreviated Mass. and Maine was sometimes abbreviated Me.
What is the abbreviation for Washington DC?
Washington DC uses DC (for District of Columbia). It is not a state but has a USPS code for mail delivery purposes.
What are the US territory abbreviations?
Puerto Rico = PR, Guam = GU, US Virgin Islands = VI, American Samoa = AS, Northern Mariana Islands = MP, and the District of Columbia = DC.
Did Nebraska change its abbreviation?
Yes. Nebraska was formerly abbreviated NB but was changed to NE by the USPS in 1969 to avoid confusion with New Brunswick, Canada (also NB). This is one reason some older documents use NB for Nebraska.
What is the difference between USPS and ISO abbreviations?
USPS abbreviations (used on mail) are 2 letters without a country prefix (e.g., CA for California). ISO 3166-2 codes add the country prefix: US-CA for California. ISO codes are used in international databases and location services.