Every ZIP code in the United States, with weather, radar, trivia and the numbers behind it. Five digits since 1963!

ZIP stands for Zone Improvement Plan. The codes went live on July 1, 1963.The lowest ZIP code is 00501 — the IRS in Holtsville, New York.The highest ZIP code is 99950, in Ketchikan, Alaska.Type 07734 into a calculator and turn it upside down: hELLO. It is Keansburg, New Jersey.12345 belongs to one company: General Electric in Schenectady, New York.The first digit is a region: 0 is New England and New Jersey, 9 is the West Coast, Alaska and Hawaii.Mr. ZIP, the cartoon mailman, was the mascot that sold the idea to America.ZIP+4 arrived in 1983 and can narrow a ZIP down to one side of one block.A ZIP code is a mail route, not a place: plenty of them cross county and even state lines.Play ZIP Hunt: guess the secret ZIP code of the day in six tries.
zipcodes.pro — PREFIX/181

ZIP codes starting with 181

ZIP codes
8
States
PA
Largest city
Allentown, PA
Population
179,222

The first three digits of a ZIP code identify a sectional center facility — the postal processing plant that sorts mail for the area. It is a mail-routing grouping, not an administrative boundary.

Every ZIP code in 181xx

ZIP codes starting with 181
ZIP City Type Population Median income Median home
18101 Allentown , PA Standard 6,120 $44,773 $171,300
18102 Allentown , PA Standard 51,001 $43,085 $163,400
18103 Allentown , PA Standard 48,746 $72,895 $272,700
18104 Allentown , PA Standard 48,683 $94,601 $336,400
18105 Allentown , PA No street area — — —
18106 Allentown , PA Standard 6,226 $92,813 $412,200
18109 Allentown , PA Standard 18,446 $58,031 $198,800
18195 Allentown , PA Standard 0 — —

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zipcodes.pro. “ZIP codes starting with 181.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/prefix/181

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