A US address is three lines — recipient, delivery line, then city, state and ZIP — and the apparent simplicity is why so many forms get it wrong. The actual standard is USPS Publication 28, which canonicalises everything the three lines contain: street suffixes (ST, AVE, BLVD), directionals (N, SW), and the secondary-unit designators where most validators overreach — APT and STE require a number, while designators like BSMT and FRNT must stand alone. The two-letter state codes are also a postal invention, defined in the same document, which is why OH is an abbreviation a tax form and a mailing label can agree on.
The ZIP code is the load-bearing element, and it is structured: five digits where the first three identify a sorting facility, plus an optional +4 that narrows to a block face or a single building. The prefix-to-state relationship is strong but not absolute — exactly five of the 911 prefixes in the 50 states and DC serve more than one state, and one more (340, inside Florida's range) belongs to military mail. Per-state prefix ranges and postal data are available on the state pages.
The city line is where imported data quietly rots. A ZIP does not determine one city name: the Postal Service files parts of Boston under Allston and Dorchester, parts of New York under neighbourhood names, and it accepts either form as correct. The reverse is worse — a city name does not determine a state, since Franklin exists in 27 jurisdictions and Washington in 26, none of them Washington state. The only stable key is the pair: resolve on city plus state, or better, on the ZIP itself.
What this page generates is a format-valid composite: a real city, its real state and a ZIP that genuinely belongs to them, drawn from one postal record, with the street name and house number invented. Above it sits a random American name — a first name and surname from the same US pools the fake name generator draws on — so the record reads as one person rather than a name bolted onto an address. That is what address-form validation, checkout testing and demo data need, and it is all it is. The street is not checked against a delivery-point database and may coincide with a real address. A generated record does not establish residency or authorization to ship there; see the acceptable-use terms.