Two kinds of city
The city in your mailing address is a postal city. The Postal Service gives each ZIP code a default city name, usually the name of the post office that serves it, and sometimes lists other acceptable names as well. It exists to get mail to you.
The city whose limits you live inside, if any, is your legal or municipal city. It decides who runs your police, fire service, zoning and local taxes, and whether you can vote in its elections. It is set by the state and by annexation, and has nothing to do with mail routes.
Most of the time the two match. When they do not, you can live in one place and have mail addressed to another, perfectly correctly.
The most common cases
- Unincorporated areas. If you live outside any city's limits, your address still needs a city name, so it gets the post office's. Millions of Americans have a city in their address that they do not live in.
- Suburbs served by a bigger city's post office. A small town may share a ZIP code, and so a postal city, with its larger neighbour.
- ZIP codes that cross city lines. Because ZIP codes follow delivery routes, one can cover parts of several cities, all using one default city name.
- Annexation. When a city annexes an area, the postal name does not automatically change, so the address can lag years behind the boundary.
Which one should I use?
For mail, packages and any form that checks your address against postal records, such as banking, credit and shipping, use the postal city exactly as it appears on your mail.
For questions about which government serves you, such as property taxes, building permits, voter registration, trash collection or which police department to call, use the legal city, or the county if you are unincorporated. Your county property appraiser or assessor's website shows it for each parcel.
Our city tool shows the place you are physically inside, based on mapped boundaries. So if it disagrees with your mail, that is usually exactly this difference, not an error.
Checking your county
The same confusion applies to counties. The postal city's county is not always your county, especially near a line. Because counties decide courts, property tax and many services, it is worth checking by position using the county tool rather than assuming from the city name.