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Where 51640 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 51640 into a pocket calculator and turn it upside down: OhgIS — not quite a word, sorry.
- ➕ As a number, 51,640 = 2 × 2 × 2 × 5 × 1291. Its digits add up to 16, a total 1,922 other ZIP codes share.
- 💾In binary, the way a computer stores it:
1100100110111000 - 🏠 Its numerical neighbours: 51639 (Farragut, IA, 12 mi away) and 51645 (Imogene, IA, 22 mi away).
- 🔄 Backwards, 51640 becomes 04615, which is not a ZIP code at all.
- 👥 78 other ZIP codes are made of exactly the same digits (01546, 01564, 05146, 05461, 05641, 06145, …). The farthest-flung twin is 01564 in Sterling, MA, 1,238 miles away.
- 🧭 Farther north than 62% of all ZIP codes, and farther west than 70%.
- 🎯163 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
- 🌏 Dig straight through the Earth from 51640 and you would come out at 40.63°S, 84.34°E — 913 miles from Port-aux-Français, French Southern Territories, the nearest big city to that spot.
- ☀Longest day of the year: 15h 05m of daylight. Shortest: 9h 16m.
- 📏 At 115.4 square miles of land, 51640 is bigger than 81% of ZIP codes — room for about 88 Central Parks.
- Working out the sun…
- Checking the USGS…
Source: USGS.
People and housing
| Population | 1,381This ZIP1,381 |
|---|---|
| Households | 588This ZIP588 |
| Housing units | 690This ZIP690 |
| Median age | 43.1This ZIP43.1Iowa38.6US 38.9 |
| Median household income | $65,385This ZIP$65,385Iowa$75,059US $80,734 |
| Median home value | $122,900This ZIP$122,900Iowa$208,000US $332,700 |
| Median gross rent | $729This ZIP$729Iowa$972US $1,413 |
| Bachelor's degree or higher | 18.4%This ZIP18.4% |
| Mean commute | 23.0 minThis ZIP23.0 min |
| Population density | 12.0 / sq miThis ZIP12.0 / sq mi |
Business and tax activity
| Business establishments | 31This ZIP31 |
|---|---|
| Employees | 415This ZIP415 |
| Annual payroll | $27,873,000This ZIP$27,873,000 |
| Tax returns filed | 590This ZIP590 |
| Total adjusted gross income | $44,260,000This ZIP$44,260,000 |
Land area
| Land area | 115.41 sq miThis ZIP115.41 sq mi |
|---|---|
| Water area | 1.56 sq miThis ZIP1.56 sq mi |
Counties 51640 spans
A ZIP code is a mail route and ignores county lines. Shares are by overlapping land area.
| County | Share of this ZIP |
|---|---|
| Fremont County | 81.9% |
| Atchison County | 18.1% |
Other place names in 51640
Census places whose land this ZIP code overlaps. The Postal Service may accept other city names in an address, too.
ZIP codes near 51640
| ZIP | City | Distance |
|---|---|---|
51650 | Riverton, IA | 6.9 mi |
64496 | Watson, MO | 9.1 mi |
68421 | Peru, NE | 10.1 mi |
51652 | Sidney, IA | 10.3 mi |
51648 | Percival, IA | 10.7 mi |
68410 | Nebraska City, NE | 11.7 mi |
51639 | Farragut, IA | 12.1 mi |
68379 | Julian, NE | 12.8 mi |
64482 | Rock Port, MO | 13.5 mi |
68321 | Brownville, NE | 15.7 mi |
Find every ZIP code within 10 miles of 51640 →
Questions about this ZIP code
Where is ZIP code 51640?
51640 is in Hamburg, Iowa, in Fremont County. Its published point location is 40.6262, -95.6614.
What county is 51640 in?
51640 spans 2 counties: Fremont County and Atchison County. Most of it falls in Fremont 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 51640?
Hamburg uses area code 712, from NANPA's telephone records.
What time zone is 51640 in?
51640 uses America/Chicago.
How many people live in 51640?
About 1,381 people live in ZIP code 51640, in 588 households, at 12.0 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 51640?
$65,385 a year, against $75,059 across Iowa.
What ZIP codes are near 51640?
The closest are 51650 (6.9 mi), 64496 (9.1 mi), 68421 (10.1 mi), 51652 (10.3 mi) and 51648 (10.7 mi).
Is 51640 a PO Box ZIP code?
51640 is a standard ZIP code. A normal ZIP code with street delivery.
Download or cite
Cite this page
zipcodes.pro. “51640 ZIP Code — Hamburg, Iowa (Fremont County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/51640
Machine-readable version of these facts:
curl https://zipcodes.pro/zip/51640.jsonUnderlying data is public domain or openly licensed — sources, vintages and licences.