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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/51521

51521

ZIP 51521 is Avoca, Iowa, mostly in Pottawattamie County; area code 712; Central time.

Type
Standard
Time zone
America/Chicago
County
Pottawattamie +1 more
Metro area
Omaha, NE-IA
Population
1,953
Coordinates
41.4855, -95.3447
☼ Live from 51521 — Avoca, IA

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Local time: —

Where 51521 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 51521
  • 🔢 Type 51521 into a pocket calculator and turn it upside down: IZSIS — not quite a word, sorry.
  • ➕ 51521 is a prime number. It cannot be divided by anything except 1 and itself. Its digits add up to 14, a total 1,416 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 1100100101000001
  • 🏠 Its numerical neighbours: 51520 (Arion, IA, 34 mi away) and 51523 (Blencoe, IA, 48 mi away).
  • 🔄 Backwards, 51521 becomes 12515 — and that is a real ZIP code: Clintondale, NY, 1,097 miles away.
  • 👥 13 other ZIP codes are made of exactly the same digits (11552, 12155, 12515, 12551, 15215, 15251, …). The farthest-flung twin is 11552 in West Hempstead, NY, 1,128 miles away.
  • 🧭 Farther north than 71% of all ZIP codes, and farther west than 69%.
  • 🎯205 miles northeast of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 51521 and you would come out at 41.49°S, 84.66°E — 884 miles from Port-aux-Français, French Southern Territories, the nearest big city to that spot.
  • ☀Longest day of the year: 15h 11m of daylight. Shortest: 9h 10m.
  • 📏 At 87.4 square miles of land, 51521 is bigger than 75% of ZIP codes — room for about 66 Central Parks.
🌙 The sky over 51521 today
  • Working out the sun…
🌋 Shake report
  • Checking the USGS…

Source: USGS.

People and housing

Population1,953This ZIP1,953
Households878This ZIP878
Housing units965This ZIP965
Median age45.2This ZIP45.2Iowa38.6US 38.9
Median household income$73,769This ZIP$73,769Iowa$75,059US $80,734
Median home value$202,800This ZIP$202,800Iowa$208,000US $332,700
Median gross rent$860This ZIP$860Iowa$972US $1,413
Bachelor's degree or higher28.0%This ZIP28.0%
Mean commute23.3 minThis ZIP23.3 min
Population density22.3 / sq miThis ZIP22.3 / sq mi

Business and tax activity

Business establishments63This ZIP63
Employees480This ZIP480
Annual payroll$27,086,000This ZIP$27,086,000
Tax returns filed1,080This ZIP1,080
Total adjusted gross income$91,811,000This ZIP$91,811,000

Land area

Land area87.41 sq miThis ZIP87.41 sq mi
Water area0.48 sq miThis ZIP0.48 sq mi

Counties 51521 spans

A ZIP code is a mail route and ignores county lines. Shares are by overlapping land area.

CountyShare of this ZIP
Pottawattamie County 69.0%
Shelby County 31.0%

Other place names in 51521

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

ZIP codes near 51521

ZIPCityDistance
51593 Harlan, IA 1.3 mi
51570 Shelby, IA 6.9 mi
51536 Hancock, IA 7.1 mi
51577 Walnut, IA 7.4 mi
51553 Minden, IA 11.6 mi
51537 Harlan, IA 11.6 mi
51552 Marne, IA 11.9 mi
51560 Oakland, IA 12.2 mi
51563 Persia, IA 13.8 mi
51565 Portsmouth, IA 14.3 mi

Find every ZIP code within 10 miles of 51521 →

Questions about this ZIP code

Where is ZIP code 51521?

51521 is in Avoca, Iowa, in Pottawattamie County, part of the Omaha, NE-IA metropolitan area. Its published point location is 41.4855, -95.3447.

What county is 51521 in?

51521 spans 2 counties: Pottawattamie County and Shelby County. Most of it falls in Pottawattamie County, measured by overlapping land area — the county holding the most land in a ZIP code is not always the one holding the most residents.

What area code is 51521?

Avoca uses area code 712, from NANPA's telephone records.

What time zone is 51521 in?

51521 uses America/Chicago.

How many people live in 51521?

About 1,953 people live in ZIP code 51521, in 878 households, at 22.3 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 51521?

$73,769 a year, against $75,059 across Iowa.

What ZIP codes are near 51521?

The closest are 51593 (1.3 mi), 51570 (6.9 mi), 51536 (7.1 mi), 51577 (7.4 mi) and 51553 (11.6 mi).

Is 51521 a PO Box ZIP code?

51521 is a standard ZIP code. A normal ZIP code with street delivery.

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Cite this page

zipcodes.pro. “51521 ZIP Code — Avoca, Iowa (Pottawattamie County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/51521

Machine-readable version of these facts:

curl https://zipcodes.pro/zip/51521.json

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