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The Strangest ZIP Codes in America

A ZIP code for Santa Claus, one for a single skyscraper, and one that changes states — these are America's oddest codes.

## Oddities of the System

The ZIP code system was designed for efficiency, but decades of growth, politics, and special cases have created some truly unusual codes.

## Santa Claus, Indiana (47579)

The town of Santa Claus, Indiana receives over **500,000 letters addressed to Santa Claus** each holiday season. Local volunteers and postal workers respond to thousands of them. The town embraces its name with a theme park (Holiday World), Santa Claus Museum, and streets named Christmas Boulevard and Candy Cane Lane.

## The Empire State Building (10118)

New York's Empire State Building has its own unique ZIP code — 10118. The building receives enough mail to justify its own sorting. Its 102 floors contain over 1,000 businesses.

Other buildings with unique ZIPs:

| Building | ZIP |
|----------|-----|
| Empire State Building | 10118 |
| Sears/Willis Tower | 60606 (shared) |
| Pentagon | 20301 |
| United Nations | 10017 |

## The Lowest and Highest

| Record | ZIP | Location |
|--------|-----|----------|
| Lowest | 00501 | IRS, Holtsville, NY |
| Lowest standard | 00601 | Adjuntas, PR |
| Highest | 99950 | Ketchikan, AK |

## Ghost ZIPs

Some ZIP codes have been retired but live on in databases:

- **10048** — World Trade Center (retired after 9/11)
- Various ZIPs in depopulated areas of Detroit, Gary, and other shrinking cities have been consolidated

## Floating ZIP Codes

Aircraft carriers and other Navy ships have FPO ZIP codes that literally float around the ocean. The USS Nimitz, for example, has been assigned FPO AP 96620 regardless of whether it's in the Pacific, Indian Ocean, or Persian Gulf.

## The Two-State ZIP

ZIP code 42223 covers Fort Campbell, a military base that straddles the Kentucky-Tennessee border. Residents on the Kentucky side and Tennessee side share the same ZIP but file taxes in different states, vote in different elections, and follow different laws.

## The Non-Contiguous ZIP

Some ZIPs consist of multiple disconnected pieces. This happens when USPS routing makes it more efficient to assign a pocket of addresses to a non-adjacent ZIP code. The result looks like islands on a map.

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Frequently Asked Questions

Where can I learn more about postal code systems?
ZipFYI's Stories section features in-depth articles about postal code systems worldwide, their history, how they work, and why they matter. Topics range from the origins of ZIP codes to how modern postal systems handle millions of packages daily.
How do postal code systems evolve over time?
Postal code systems evolve to accommodate population growth, urbanization, and changes in mail volume. New codes are created when areas develop, codes may be reassigned when delivery routes change, and entire systems can be reformed (as Ireland did with Eircode in 2015).
Why are postal codes important for businesses?
Businesses use postal codes for shipping and logistics, sales tax calculation, market analysis, customer demographics, delivery zone determination, insurance underwriting, and compliance with regulations. Accurate postal codes reduce delivery failures and improve customer experience.
How do postal codes relate to demographics?
In the US, the Census Bureau links demographic data to ZIP Code Tabulation Areas (ZCTAs). This enables analysis of population, income, education, housing, and commute patterns at the postal code level. Marketers, researchers, and policy makers rely on this data extensively.
What is geocoding and how does it relate to postal codes?
Geocoding converts addresses and postal codes into geographic coordinates (latitude/longitude). It enables mapping, distance calculations, delivery routing, and spatial analysis. Postal codes serve as a common input for geocoding services because they provide approximate location data.