For residents of Waban, Mass., remembering the city’s designated ZIP code is as easy as 02468.
The same could be said for folks in Errol, N.H., who enjoy the memorable numeric code of 03579, or in Kerby, Ore., who count odd numbers backward for their mail routing address of 97531.
Like prime pieces of real estate, such user-friendly ZIPs are based on location, location, location.
Since the U.S. Postal Service began assigning five-number ZIPs (as part of the Zoning Improvement Plan) in 1963 to better manage increasing volumes of mail across America, the code’s first numbers have represented a general geographic area of the nation—0 in the East, moving to 9 in the West. The next two numbers represent regional areas, and the final two identify specific post offices.
The nation’s highest ZIP code is 99950 in Ketchikan, Alaska, and the lowest is 00501, which routes mail to the Internal Revenue Service Processing Center in Holtsville, N.Y.
Other notable designations, according to the USPS, include the nation’s “luckiest” ZIP codes—07110 in Newark, N.J., and 70011 in Metairie, La.; the binary ZIP of 10101 in New York City; the “dance step” ZIP of 12121 in Melrose, N.Y.; and the 43210 “countdown code” in Columbus, Ohio.
Only one residence in America is assigned its own ZIP code. Mail addressed to the White House is routed via 20500.