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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 — ZIP/18104

18104

ZIP 18104 is in Allentown, Pennsylvania, in Lehigh County; area codes 484, 610 and 835; Eastern time. Allentown has 8 ZIP codes in all.

Type
Standard
Time zone
America/New_York
County
Lehigh
Population
48,683
Coordinates
40.6117, -75.5469
☼ Live from 18104 — Allentown, PA

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Where 18104 is

Approximate ZIP boundary (Census ZCTA 2020). ZIP codes are mail routes, not areas, so the shape shown is the Census tabulation area that approximates it.

★ Weird and wonderful facts about 18104
  • 🔢 Type 18104 into a pocket calculator and turn it upside down: hOIBI — not quite a word, sorry.
  • ➕ As a number, 18,104 = 2 × 2 × 2 × 31 × 73. Its digits add up to 14, a total 1,416 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 100011010111000
  • 🏠 Its numerical neighbours: 18103 (Allentown, PA, 4 mi away) and 18105 (Allentown, PA, 3 mi away).
  • 🔄 Backwards, 18104 becomes 40181, which is not a ZIP code at all.
  • 👥 23 other ZIP codes are made of exactly the same digits (01841, 11804, 14081, 14108, 14801, 14810, …). The farthest-flung twin is 84110 in Salt Lake City, UT, 1,893 miles away.
  • 🧭 Farther north than 62% of all ZIP codes, and farther east than 86%.
  • 🎯1,213 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 18104 and you would come out at 40.61°S, 104.45°E — 871 miles from Perth, Australia, the nearest big city to that spot.
  • ☀Longest day of the year: 15h 05m of daylight. Shortest: 9h 16m.
  • 📏 At 23.0 square miles of land, 18104 is bigger than 40% of ZIP codes — room for about 17 Central Parks.
🌙 The sky over 18104 today
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🌋 Shake report
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Source: USGS.

People and housing

Population48,683This ZIP48,683
Households18,532This ZIP18,532
Housing units19,193This ZIP19,193
Median age40.6This ZIP40.6Pennsylvania40.9US 38.9
Median household income$94,601This ZIP$94,601Pennsylvania$77,971US $80,734
Median home value$336,400This ZIP$336,400Pennsylvania$254,500US $332,700
Median gross rent$1,637This ZIP$1,637Pennsylvania$1,209US $1,413
Bachelor's degree or higher46.1%This ZIP46.1%
Mean commute21.5 minThis ZIP21.5 min
Population density2,121.1 / sq miThis ZIP2,121.1 / sq mi

Business and tax activity

Business establishments1,248This ZIP1,248
Employees25,626This ZIP25,626
Annual payroll$1,519,653,000This ZIP$1,519,653,000
Tax returns filed24,340This ZIP24,340
Total adjusted gross income$2,391,821,000This ZIP$2,391,821,000

Land area

Land area22.95 sq miThis ZIP22.95 sq mi
Water area0.19 sq miThis ZIP0.19 sq mi

Other place names in 18104

Census places whose land this ZIP code overlaps. The Postal Service may accept other city names in an address, too.

ZIP codes near 18104

ZIPCityDistance
18105 Allentown, PA 3.0 mi
18106 Allentown, PA 3.4 mi
18069 Orefield, PA 3.7 mi
18102 Allentown, PA 3.7 mi
18052 Whitehall, PA 3.9 mi
18101 Allentown, PA 4.1 mi
18103 Allentown, PA 4.2 mi
18046 East Texas, PA 4.5 mi
18195 Allentown, PA 4.5 mi
18087 Trexlertown, PA 4.5 mi

Find every ZIP code within 10 miles of 18104 →

Questions about this ZIP code

Where is ZIP code 18104?

18104 is in Allentown, Pennsylvania, in Lehigh County, part of the Allentown-Bethlehem-Easton, PA-NJ metropolitan area. Its published point location is 40.6117, -75.5469.

What county is 18104 in?

18104 lies in Lehigh County.

What area code is 18104?

Allentown uses area codes 484, 610 and 835, from NANPA's telephone records.

What time zone is 18104 in?

18104 uses America/New_York.

How many people live in 18104?

About 48,683 people live in ZIP code 18104, in 18,532 households, at 2,121.1 people per square mile. These are American Community Survey 5-year estimates for the ZIP Code Tabulation Area, not a headcount.

What is the median household income in 18104?

$94,601 a year, against $77,971 across Pennsylvania.

What ZIP codes are near 18104?

The closest are 18105 (3 mi), 18106 (3.4 mi), 18069 (3.7 mi), 18102 (3.7 mi) and 18052 (3.9 mi).

Is 18104 a PO Box ZIP code?

18104 is a standard ZIP code. A normal ZIP code with street delivery.

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Cite this page

zipcodes.pro. “18104 ZIP Code — Allentown, Pennsylvania (Lehigh County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/18104

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