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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/18101

18101

ZIP 18101 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
6,120
Coordinates
40.6032, -75.4695
☼ Live from 18101 — Allentown, PA

Weather right now

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Local time: —

Where 18101 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 18101
  • 🔢 Type 18101 into a pocket calculator and turn it upside down: IOIBI — not quite a word, sorry.
  • ➕ As a number, 18,101 = 23 × 787. Its digits add up to 11, a total 714 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 100011010110101
  • 🏠 Its numerical neighbours: 18099 (Emmaus, PA, 5 mi away) and 18102 (Allentown, PA, 0 mi away).
  • 🔄 Backwards, 18101 becomes 10181, which is not a ZIP code at all.
  • 👥 7 other ZIP codes are made of exactly the same digits (01118, 10118, 11801, 18011, 80111, 81011, …). The farthest-flung twin is 81101 in Alamosa, CO, 1,637 miles away.
  • 🧭 Farther north than 62% of all ZIP codes, and farther east than 86%.
  • 🎯1,217 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 18101 and you would come out at 40.60°S, 104.53°E — 868 miles from Perth, Australia, the nearest big city to that spot.
  • ☀Longest day of the year: 15h 05m of daylight. Shortest: 9h 16m.
  • 📏 At 0.307 square miles of land, 18101 is bigger than 4% of ZIP codes — about 149 football fields.
🌙 The sky over 18101 today
  • Working out the sun…
🌋 Shake report
  • Checking the USGS…

Source: USGS.

People and housing

Population6,120This ZIP6,120
Households2,576This ZIP2,576
Housing units2,786This ZIP2,786
Median age29.1This ZIP29.1Pennsylvania40.9US 38.9
Median household income$44,773This ZIP$44,773Pennsylvania$77,971US $80,734
Median home value$171,300This ZIP$171,300Pennsylvania$254,500US $332,700
Median gross rent$1,430This ZIP$1,430Pennsylvania$1,209US $1,413
Bachelor's degree or higher23.2%This ZIP23.2%
Mean commute28.8 minThis ZIP28.8 min
Population density19,934.9 / sq miThis ZIP19,934.9 / sq mi

Business and tax activity

Business establishments329This ZIP329
Employees5,736This ZIP5,736
Annual payroll$523,509,000This ZIP$523,509,000
Tax returns filed2,430This ZIP2,430
Total adjusted gross income$108,072,000This ZIP$108,072,000

Land area

Land area0.31 sq miThis ZIP0.31 sq mi
Water area0.00 sq miThis ZIP0.00 sq mi

Other place names in 18101

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

ZIP codes near 18101

ZIPCityDistance
18102 Allentown, PA 0.5 mi
18105 Allentown, PA 1.1 mi
18103 Allentown, PA 2.5 mi
18109 Allentown, PA 2.7 mi
18032 Catasauqua, PA 3.7 mi
18104 Allentown, PA 4.1 mi
18052 Whitehall, PA 4.2 mi
18018 Bethlehem, PA 4.2 mi
18098 Emmaus, PA 4.6 mi
18099 Emmaus, PA 4.6 mi

Find every ZIP code within 10 miles of 18101 →

Questions about this ZIP code

Where is ZIP code 18101?

18101 is in Allentown, Pennsylvania, in Lehigh County, part of the Allentown-Bethlehem-Easton, PA-NJ metropolitan area. Its published point location is 40.6032, -75.4695.

What county is 18101 in?

18101 lies in Lehigh County.

What area code is 18101?

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

What time zone is 18101 in?

18101 uses America/New_York.

How many people live in 18101?

About 6,120 people live in ZIP code 18101, in 2,576 households, at 19,934.9 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 18101?

$44,773 a year, against $77,971 across Pennsylvania.

What ZIP codes are near 18101?

The closest are 18102 (0.5 mi), 18105 (1.1 mi), 18103 (2.5 mi), 18109 (2.7 mi) and 18032 (3.7 mi).

Is 18101 a PO Box ZIP code?

18101 is a standard ZIP code. A normal ZIP code with street delivery.

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Cite this page

zipcodes.pro. “18101 ZIP Code — Allentown, Pennsylvania (Lehigh County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/18101

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