How an address is written in United States

The postal format table for United States — the order the lines go in, the parts its operator requires, what it calls them, and the words it prints on a box — and, separately, what this server actually holds for United States, so the page never implies a check it cannot run.

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Response

Look up any address to see the full API response, straight from the live service. The country decides which format it is read against.

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The order the lines go in

The parts are named rather than filled in: Spaw does not know an address in United States and will not invent one. This block is produced by the same function that rewrites a real address, so the line order, the capitals United States asks for and any text its operator prints on every envelope are the checker's own behaviour rather than a second description of it.

Organisation
12 Street name
Flat or unit
TOWN OR CITY, STATE ZIP code

No recipient line: nothing in the response is about a person, so the name the envelope carries is not part of what is checked.

field	called here	required	capitals
organization	Organisation	optional	—
addressLine1	Street name	required	—
addressLine2	Flat or unit	optional	—
locality	Town or city	required	yes
administrativeArea	State	required	yes
postalCode	ZIP code	required	—

No house-number rule is carried for United States, so the international default is used: the house number comes before the street name. The ZIP code is written after the town.

The ZIP code

United States ZIP codes are checked against the pattern below rather than a description of it, because the shape is too particular to summarise without losing a case.

pattern (\d{5})(?:[ \-](\d{4}))?

A national directory is installed for United States, so a ZIP code here is not only checked for shape but looked up: 41,488 codes from geonames-postal-codes, version 2026-09-17, of which 41,488 are live and 0 have been retired. A retired code is usually a real address with an out-of-date code rather than a typo, so it is scored rather than refused.

What United States calls an address that is not a front door

The words below are United States's own, taken from its postal operator's addressing guide, and they are the words the checker reads. Because they are carried, an address here with none of them answers street.

address_type	written as
private_mailbox Private mailbox at a mail-receiving agency	PMB
po_box Post-office box	PO BOX, P O BOX, POST OFFICE BOX, POB; CALLER, FIRM CALLER, BIN, LOCKBOX, DRAWER (only at the start of a line, with a number)
general_delivery Held at the counter for collection	GENERAL DELIVERY
military Military and diplomatic mail	APO, FPO, DPO; PSC, CMR (only at the start of a line, with a number)
rural_route Rural route	RR, HC, RFD, RURAL ROUTE, HIGHWAY CONTRACT, STAR ROUTE (only at the start of a line, with a number)

The anchored spellings are the conservative half of this: those words are ordinary language elsewhere in an address, so they only count when they open the line and carry a number after them.

The state codes

62 codes, which is what lets a written address be split at all — and the state written out in full is folded onto its code, so the two spellings are read as the same place.

AL Alabama
AK Alaska
AS American Samoa
AZ Arizona
AR Arkansas
AA Armed Forces (AA)
AE Armed Forces (AE)
AP Armed Forces (AP)
CA California
CO Colorado
CT Connecticut
DE Delaware
DC District of Columbia
FL Florida
GA Georgia
GU Guam
HI Hawaii
ID Idaho
IL Illinois
IN Indiana
IA Iowa
KS Kansas
KY Kentucky
LA Louisiana
ME Maine
MH Marshall Islands
MD Maryland
MA Massachusetts
MI Michigan
FM Micronesia
MN Minnesota
MS Mississippi
MO Missouri
MT Montana
NE Nebraska
NV Nevada
NH New Hampshire
NJ New Jersey
NM New Mexico
NY New York
NC North Carolina
ND North Dakota
MP Northern Mariana Islands
OH Ohio
OK Oklahoma
OR Oregon
PW Palau
PA Pennsylvania
PR Puerto Rico
RI Rhode Island
SC South Carolina
SD South Dakota
TN Tennessee
TX Texas
UT Utah
VT Vermont
VI Virgin Islands
VA Virginia
WA Washington
WV West Virginia
WI Wisconsin
WY Wyoming

What can be checked for a United States address

Read from the datasets this server holds right now, not written into the page. For most countries the answer is the written form and the postcode shape and nothing beyond them — in particular not the row people assume is always there. An address can be perfectly formed and still not exist, and where no register is installed nothing here will pretend to know which.

check	for US	what the answer means
Written form	yes	The address is split into United States's own parts and rewritten in the order above. A missing required part is named in one typed reason rather than a general failure.
ZIP code pattern	yes	Checked against the pattern the table carries for United States. A value that does not match answers invalid_postal_code.
ZIP code exists	yes	41,488 codes from geonames-postal-codes, live and terminated ones apart, so a retired code reads as retired rather than as a typo.
Kind of delivery point	yes	United States's own box naming is carried, so an address with no marker answers street rather than unknown.
Street exists	yes	The address register carries every street its buildings stand on, so match_level answers street when the street is known and the building is not.
Building exists	yes	84,692,955 addresses from us-national-address-database. It covers part of the country, so a match answers exists: true and a miss still answers null.
Companies at the address	yes	An open company register is installed for this country, so the number of companies giving the address as their registered office is counted, and a published threshold marks it as a mail drop.
Known mailbox branch	yes	Mailbox operators' own published branch lists cover this country, and the answer names the operator that matched.
Post actually arrives	no	Not from this page, and not from open data in any country: whether post is delivered, and the vacant, residential and agency flags that go with it, are the postal service's own licensed product. Those fields answer deliverability_checked: false rather than a guess.

Null means not evaluated, never no. How to read an address-existence answer sets out what a premise, street or postcode match proves, and what absence proves.

Other countries

address-formats 2026-09-05 · address-rules 2026-09-17 · us-national-address-database 2026-09-06 · geonames-postal-codes 2026-09-17 · company-registers 2026-09-01 · mail-drop-locations 2026-09-12 · checked 2026-09-18

Wrong result, or is it about you? If this tool said something you think is wrong, tell us and a person reads it. If Spaw is holding data about you and you never signed up here — a customer may have had your address verified, or reported that a message to it bounced — erase it yourself, confirmed by mail to that address and with no account needed.

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