City to ZIP Code

Looking up all ZIP codes for a US city is the reverse of the ZIP-to-city lookup, and it solves a different but equally important problem: when you know where you want to target, you need the complete ZIP code list for that location. Our City to ZIP Code tool returns every ZIP code for which your entered city is the USPS preferred city name, plus ZIP codes where your city is an acceptable alternate name — giving you comprehensive coverage of the city postal geography.

Why One City Has Multiple ZIP Codes

Cities are served by multiple ZIP codes because USPS divides each city delivery area into zones based on mail volume, delivery route geography, and population density. A small town with 5,000 people might have a single ZIP code covering the entire community. A medium city of 100,000 might have 5–10 ZIP codes dividing the city into north, south, east, west, and downtown zones. A major city like Houston (population ~2.3 million) has approximately 74 ZIP codes covering distinct neighborhoods, suburbs, and industrial areas. New York City, the largest US city by population, has ~178 ZIP codes across its five boroughs.

The boundaries between ZIP codes within a city generally follow major streets, rail lines, or natural features. In grid-plan cities, ZIP boundaries often follow north-south or east-west arterials, creating roughly rectangular ZIP code zones. In cities with more complex topography or street patterns, ZIP boundaries may be irregular.

Preferred City vs. Alternate City in ZIP Lookups

When you search for a city, our tool returns ZIP codes in two categories. ZIP codes where your city is the USPS preferred city name are shown first — these are ZIPs that officially carry your city name as their primary designation. ZIP codes where your city is an acceptable alternate city name are shown second — these are ZIPs whose preferred name is a different community (often a smaller suburb or neighborhood), but which USPS will accept mail addressed to your city name.

For example, searching "Los Angeles, CA" returns ZIPs where "Los Angeles" is the preferred name, but also ZIPs in areas like Watts, Palms, Boyle Heights, and other communities that USPS delivers to under the Los Angeles alternate name even though those neighborhoods have their own community identities.

Duplicate City Names Across States

There are thousands of duplicate city names across US states — over 600 US cities named Springfield across multiple states, for instance. When searching by city name, always specify the state to get the correct results. Without a state specification, a search for "Portland" could match Oregon (OR) or Maine (ME). Our tool requires city + state for unambiguous lookup.

City to ZIP for Direct Mail and Campaign Targeting

The most common reason to look up ZIP codes by city is for direct mail or digital ad targeting. "Target all households in Chicago" → retrieve all Chicago ZIP codes → use that list in your EDDM (Every Door Direct Mail) order or Google Ads geographic targeting. This approach ensures your campaign covers the city comprehensively without accidentally including neighboring suburbs unless you specifically intend to.

Understanding ZIP Code Coverage vs. City Limits

The ZIP codes returned for a city represent ZIPs where USPS uses that city as the preferred or acceptable mailing name — not the ZIP codes whose geographic boundaries fall within the city's incorporated limits. These two sets are often different. ZIP codes may extend beyond city limits into unincorporated suburbs while still using the city's name. And some ZIP codes within a city's boundaries may carry the name of a neighborhood or annexed community rather than the city's main name.

For political boundaries and municipal services, use the incorporated city limits shapefile from the Census Bureau TIGER/Line files. For postal addressing, the USPS city-ZIP assignment in our tool is the authoritative reference.

City to ZIP for E-Commerce and Delivery

Online retailers building geographic delivery zones frequently need to translate "deliver to Chicago" into a specific ZIP code list for their shipping rate table configuration. City-to-ZIP provides that list. For complex metropolitan areas, the city-level ZIP list may be a starting point that is then refined by adding neighboring suburb ZIPs (using ZIPs Within Radius) and removing industrial-only ZIPs that have no residential delivery addresses.