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Where 57521 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 57521 into a pocket calculator and turn it upside down: IZSLS — not quite a word, sorry.
- ➕ As a number, 57,521 = 97 × 593. Its digits add up to 20, a total 2,586 other ZIP codes share.
- 💾In binary, the way a computer stores it:
1110000010110001 - 🏠 Its numerical neighbours: 57520 (Agar, SD, 88 mi away) and 57522 (Blunt, SD, 78 mi away).
- 🔄 Backwards, 57521 becomes 12575 — and that is a real ZIP code: Rock Tavern, NY, 1,377 miles away.
- 👥 31 other ZIP codes are made of exactly the same digits (12575, 15257, 15275, 15725, 15752, 17255, …). The farthest-flung twin is 12575 in Rock Tavern, NY, 1,377 miles away.
- 🧭 Farther north than 87% of all ZIP codes, and farther west than 80%.
- 🎯305 miles northwest of the geographic center of the Lower 48, near Lebanon, Kansas.
- 🌏 Dig straight through the Earth from 57521 and you would come out at 43.79°S, 78.82°E — 560 miles from Port-aux-Français, French Southern Territories, the nearest big city to that spot.
- ☀Longest day of the year: 15h 28m of daylight. Shortest: 8h 55m.
- 📏 At 428.0 square miles of land, 57521 is bigger than 97% of ZIP codes — room for about 325 Central Parks.
- Working out the sun…
- Checking the USGS…
Source: USGS.
People and housing
| Population | 314This ZIP314 |
|---|---|
| Households | 65This ZIP65 |
| Housing units | 105This ZIP105 |
| Median age | 30.0This ZIP30.0South Dakota38.0US 38.9 |
| Median household income | $57,813This ZIP$57,813South Dakota$75,081US $80,734 |
| Bachelor's degree or higher | 25.1%This ZIP25.1% |
| Mean commute | 27.7 minThis ZIP27.7 min |
| Population density | 0.7 / sq miThis ZIP0.7 / sq mi |
Land area
| Land area | 427.98 sq miThis ZIP427.98 sq mi |
|---|---|
| Water area | 2.31 sq miThis ZIP2.31 sq mi |
Counties 57521 spans
A ZIP code is a mail route and ignores county lines. Shares are by overlapping land area.
| County | Share of this ZIP |
|---|---|
| Mellette County | 50.3% |
| Jackson County | 49.7% |
Other place names in 57521
Census places whose land this ZIP code overlaps. The Postal Service may accept other city names in an address, too.
ZIP codes near 57521
| ZIP | City | Distance |
|---|---|---|
57562 | Okaton, SD | 13.3 mi |
57543 | Kadoka, SD | 17.2 mi |
57547 | Long Valley, SD | 24.1 mi |
57560 | Norris, SD | 24.6 mi |
57579 | White River, SD | 24.7 mi |
57559 | Murdo, SD | 24.9 mi |
57577 | Wanblee, SD | 30.0 mi |
57552 | Midland, SD | 32.5 mi |
57566 | Parmelee, SD | 33.7 mi |
57567 | Philip, SD | 35.2 mi |
Find every ZIP code within 10 miles of 57521 →
Questions about this ZIP code
Where is ZIP code 57521?
57521 is in Belvidere, South Dakota, in Mellette County. Its published point location is 43.7921, -101.1828.
What county is 57521 in?
57521 spans 2 counties: Mellette County and Jackson County. Most of it falls in Mellette 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 57521?
Belvidere uses area code 605, from NANPA's telephone records.
What time zone is 57521 in?
57521 uses America/Chicago.
How many people live in 57521?
About 314 people live in ZIP code 57521, in 65 households, at 0.7 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 57521?
$57,813 a year, against $75,081 across South Dakota.
What ZIP codes are near 57521?
The closest are 57562 (13.3 mi), 57543 (17.2 mi), 57547 (24.1 mi), 57560 (24.6 mi) and 57579 (24.7 mi).
Is 57521 a PO Box ZIP code?
57521 is a standard ZIP code. A normal ZIP code with street delivery.
Download or cite
Cite this page
zipcodes.pro. “57521 ZIP Code — Belvidere, South Dakota (Mellette County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/57521
Machine-readable version of these facts:
curl https://zipcodes.pro/zip/57521.jsonUnderlying data is public domain or openly licensed — sources, vintages and licences.