Weather right now
Asking the National Weather Service…
Where 51231 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.
- 🔢 Type 51231 into a pocket calculator and turn it upside down: IEZIS — not quite a word, sorry.
- ➕ As a number, 51,231 = 3 × 17077. Its digits add up to 12, a total 940 other ZIP codes share.
- 💾In binary, the way a computer stores it:
1100100000011111 - 🏠 Its numerical neighbours: 51230 (Alvord, IA, 34 mi away) and 51232 (Ashton, IA, 14 mi away).
- 🔄 Backwards, 51231 becomes 13215 — and that is a real ZIP code: Syracuse, NY, 983 miles away.
- 👥 29 other ZIP codes are made of exactly the same digits (11235, 11352, 12153, 12513, 12531, 13152, …). The farthest-flung twin is 32115 in Daytona Beach, FL, 1,259 miles away.
- 🧭 Farther north than 83% of all ZIP codes, and farther west than 71%.
- 🎯270 miles northeast of the geographic center of the Lower 48, near Lebanon, Kansas.
- 🌏 Dig straight through the Earth from 51231 and you would come out at 43.11°S, 84.26°E — 796 miles from Port-aux-Français, French Southern Territories, the nearest big city to that spot.
- ☀Longest day of the year: 15h 22m of daylight. Shortest: 8h 59m.
- 📏 At 24.2 square miles of land, 51231 is bigger than 41% of ZIP codes — room for about 18 Central Parks.
- Working out the sun…
- Checking the USGS…
Source: USGS.
People and housing
| Population | 562This ZIP562 |
|---|---|
| Households | 141This ZIP141 |
| Housing units | 143This ZIP143 |
| Median age | 15.1This ZIP15.1Iowa38.6US 38.9 |
| Median household income | $108,058This ZIP$108,058Iowa$75,059US $80,734 |
| Median home value | $189,500This ZIP$189,500Iowa$208,000US $332,700 |
| Bachelor's degree or higher | 33.5%This ZIP33.5% |
| Mean commute | 26.1 minThis ZIP26.1 min |
| Population density | 23.2 / sq miThis ZIP23.2 / sq mi |
Business and tax activity
| Business establishments | 6This ZIP6 |
|---|---|
| Employees | 63This ZIP63 |
| Annual payroll | $3,385,000This ZIP$3,385,000 |
| Tax returns filed | 140This ZIP140 |
| Total adjusted gross income | $9,966,000This ZIP$9,966,000 |
Land area
| Land area | 24.21 sq miThis ZIP24.21 sq mi |
|---|---|
| Water area | 0.00 sq mi |
Other place names in 51231
Census places whose land this ZIP code overlaps. The Postal Service may accept other city names in an address, too.
ZIP codes near 51231
| ZIP | City | Distance |
|---|---|---|
51245 | Primghar, IA | 7.3 mi |
51238 | Hospers, IA | 7.9 mi |
51248 | Sanborn, IA | 8.0 mi |
51201 | Sheldon, IA | 8.2 mi |
51022 | Granville, IA | 10.3 mi |
51046 | Paullina, IA | 10.4 mi |
51232 | Ashton, IA | 13.5 mi |
51244 | Matlock, IA | 13.7 mi |
51009 | Calumet, IA | 14.7 mi |
51003 | Alton, IA | 14.7 mi |
Find every ZIP code within 10 miles of 51231 →
Questions about this ZIP code
Where is ZIP code 51231?
51231 is in Archer, Iowa, in O'Brien County. Its published point location is 43.1057, -95.7413.
What county is 51231 in?
51231 lies in O'Brien County.
What area code is 51231?
Archer uses area code 712, from NANPA's telephone records.
What time zone is 51231 in?
51231 uses America/Chicago.
How many people live in 51231?
About 562 people live in ZIP code 51231, in 141 households, at 23.2 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 51231?
$108,058 a year, against $75,059 across Iowa.
What ZIP codes are near 51231?
The closest are 51245 (7.3 mi), 51238 (7.9 mi), 51248 (8 mi), 51201 (8.2 mi) and 51022 (10.3 mi).
Is 51231 a PO Box ZIP code?
51231 is a standard ZIP code. A normal ZIP code with street delivery.
Download or cite
Cite this page
zipcodes.pro. “51231 ZIP Code — Archer, Iowa (O'Brien County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/51231
Machine-readable version of these facts:
curl https://zipcodes.pro/zip/51231.jsonUnderlying data is public domain or openly licensed — sources, vintages and licences.