The Three Lines of a Standardized US Address
The three lines of a standardized US address are the recipient line, the delivery address line, and the last line, in that fixed order, per USPS Publication 28. The recipient line carries a name or attention line; the delivery address line carries the street number, street name, and any secondary unit; the last line carries the city, the two-letter state abbreviation, and the ZIP code, ideally in ZIP+4 form.
USPS Publication 28 distinguishes a "complete" address from a "standardized" one. Complete means every element needed to match the ZIP+4 and City State files is present, and standardized means those elements use the official USPS abbreviations rather than a spelled-out or locally invented variant (USPS Publication 28).
This ordering is not cosmetic. Automated mail-processing equipment reads the last line first, to sort mail by ZIP code before it ever looks at the street address, which is why the last line's format — city, state, ZIP — is fixed and abbreviated, while the delivery address line has more room for variation between a rural route, a PO box, and a standard street address. Fake Addresses follows this identical three-line order for every US record it generates, specifically so a record copy-pasted straight into a form behaves the same way a real standardized address would.
Street Suffix and Directional Abbreviations
Street suffix and directional abbreviations are set centrally by USPS Publication 28 Appendix C1, not left to local convention, specifically so automated sorting equipment can read them consistently nationwide. AVENUE becomes AVE, BOULEVARD becomes BLVD, STREET becomes ST, DRIVE becomes DR, and CIRCLE becomes CIR — dozens of suffixes each collapse to one standard abbreviation (USPS Publication 28).
Directionals follow the same logic: North, South, East, and West abbreviate to N, S, E, and W when they appear before a street name, and the same letters apply after it for quadrant designators in cities laid out on a grid. A street called 'North Maple Avenue Northeast' standardizes to 'N MAPLE AVE NE.'
Suffix distribution also varies meaningfully by place — a coastal town's street network leans toward DR and LN while a downtown grid leans toward ST and AVE — which is why Fake Addresses tracks suffix frequency per [ZIP Code Tabulation Area]() rather than applying one national assumption everywhere. Applying this same abbreviation table to every generated street name is what keeps output postal-format-valid before delivery is even a question, and it is why two Fake Addresses records from different cities can carry noticeably different suffix mixes while both stay correctly formatted, each still traceable back to the real road-network data (U.S. the national statistical agency) it was drawn from.
Apartment, Suite and Unit Designators
Apartment, suite, and unit designators sit on the delivery address line immediately after the street name, using another set of USPS-standard abbreviations: APT for apartment, STE for suite, UNIT for unit, FL for floor, RM for room (USPS Publication 28). A missing unit number is one of the most common reasons a multi-family address fails delivery — the street segment resolves, but automated equipment cannot route the piece to a specific mailbox without it.
USPS Publication 28 places the unit designator and number on the same delivery-address line as the street, not the recipient line above it, separated from the street address by a single space: '123 MAPLE AVE APT 4B', not a separate line reading only 'APT 4B'. Some older systems still accept the two-line form, but the single-line form is what current automated equipment expects.
Fake Addresses includes a unit designator on a configurable share of generated records specifically so a QA suite can test both the bare-street-address case and the unit-designator case without hand-authoring the second scenario separately. Getting this wrong is a common test gap: a form that accepts a bare street address but silently drops everything typed after it loses real customers, not just test records, which is exactly the kind of defect a deliberately varied test set exists to catch.
A Valid US Address Example
A worked example makes the three-line structure concrete. A standardized, USPS Publication 28-formatted US address looks like this:
``
JANE DOE
123 MAPLE AVE APT 4B
AUSTIN TX 78701-1234
``
Every element follows the rules described above. The recipient line is separate from the delivery address, the street suffix is abbreviated (AVE, not Avenue), and the unit designator sits on the same line as the street. The last line uses the two-letter state abbreviation and the full ZIP+4, not just the five-digit ZIP code.
A record generated by Fake Addresses is built to this exact shape — every field in the right place, every abbreviation matching USPS Publication 28 Appendix C1 — with one deliberate difference from a real piece of mail: the street number on the delivery address line is drawn from a range the Postal Service has never assigned to a delivery point on that street, so "Jane Doe" at that address is not a real resident and the ZIP+4 does not resolve to an assigned mailbox. That is the entire difference between a Fake Addresses record and a real mailing address: identical formatting, deliberately absent deliverability — exactly the property a form-validation test needs, and a production mail run must never produce.
Frequently asked questions
What is a valid US address example?
A valid, standardized US address reads: recipient name on the first line, street number and name with official abbreviations on the second line, and city, two-letter state, and ZIP+4 on the third — for example, '123 MAIN ST APT 2, AUSTIN TX 78701-1234'. Valid here means correctly formatted, not necessarily deliverable; the two properties are checked separately.
How do I check a USPS address format?
Run it through a format/parser check, confirming street number, street name, suffix, city, state, and ZIP code are present and correctly ordered, separately from a Delivery Point Validation check, which confirms the specific number is an assigned, deliverable point. Fake Addresses output is built to pass the first and fail the second.
What is the correct apartment format for a USPS address?
The unit designator — APT, STE, UNIT, FL, RM — goes on the same line as the street address, directly after the street name, as in '123 MAPLE AVE APT 4B', not on a separate line. USPS Publication 28 treats a missing or misplaced unit number as a common cause of failed delivery for multi-family addresses.
What are the official USPS street suffix abbreviations?
USPS Publication 28 Appendix C1 sets one official abbreviation per suffix: AVENUE to AVE, BOULEVARD to BLVD, STREET to ST, DRIVE to DR, CIRCLE to CIR, and dozens more. Fake Addresses applies the same table to every generated street name pulled from public road data.
Sources
- United States Postal Service — Postal Explorer — USPS Publication 28 defines a "standardized address" as one using official USPS abbreviations, and a "complete address" as one containing everything needed to match the ZIP+4 and City State files.
- United States Postal Service — Postal Explorer — USPS Publication 28 Appendix C1 sets the official street-suffix abbreviation table (for example AVENUE to AVE, BOULEVARD to BLVD).
- U.S. the national statistical agency — A ZCTA (ZIP Code Tabulation Area) is a the national statistical agency geographic approximation of a ZIP Code built from Census tabulation blocks; not every valid ZIP Code has a 2020 ZCTA.