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Where 21788 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 21788 into a pocket calculator and turn it upside down: BBLIZ — not quite a word, sorry.
- ➕ As a number, 21,788 = 2 × 2 × 13 × 419. Its digits add up to 26, a total 2,038 other ZIP codes share.
- 💾In binary, the way a computer stores it:
101010100011100 - 🏠 Its numerical neighbours: 21787 (Taneytown, MD, 14 mi away) and 21790 (Tuscarora, MD, 23 mi away).
- 🔄 Backwards, 21788 becomes 88712, which is not a ZIP code at all.
- 👥 13 other ZIP codes are made of exactly the same digits (12788, 12878, 12887, 17882, 18827, 27818, …). The farthest-flung twin is 87821 in Datil, NM, 1,732 miles away.
- 🧭 Farther north than 53% of all ZIP codes, and farther east than 80%.
- 🎯1,123 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
- 🌏 Dig straight through the Earth from 21788 and you would come out at 39.59°S, 102.59°E — 911 miles from Perth, Australia, the nearest big city to that spot.
- ☀Longest day of the year: 14h 58m of daylight. Shortest: 9h 22m.
- 📏 At 65.4 square miles of land, 21788 is bigger than 67% of ZIP codes — room for about 50 Central Parks.
- Working out the sun…
- Checking the USGS…
Source: USGS.
People and housing
| Population | 11,654This ZIP11,654 |
|---|---|
| Households | 4,649This ZIP4,649 |
| Housing units | 4,871This ZIP4,871 |
| Median age | 44.6This ZIP44.6Maryland39.4US 38.9 |
| Median household income | $98,856This ZIP$98,856Maryland$103,678US $80,734 |
| Median home value | $379,200This ZIP$379,200Maryland$419,900US $332,700 |
| Median gross rent | $959This ZIP$959Maryland$1,705US $1,413 |
| Bachelor's degree or higher | 31.3%This ZIP31.3% |
| Mean commute | 28.7 minThis ZIP28.7 min |
| Population density | 178.1 / sq miThis ZIP178.1 / sq mi |
Business and tax activity
| Business establishments | 216This ZIP216 |
|---|---|
| Employees | 3,063This ZIP3,063 |
| Annual payroll | $161,687,000This ZIP$161,687,000 |
| Tax returns filed | 6,060This ZIP6,060 |
| Total adjusted gross income | $480,622,000This ZIP$480,622,000 |
Land area
| Land area | 65.45 sq miThis ZIP65.45 sq mi |
|---|---|
| Water area | 0.51 sq miThis ZIP0.51 sq mi |
Other place names in 21788
Census places whose land this ZIP code overlaps. The Postal Service may accept other city names in an address, too.
ZIP codes near 21788
| ZIP | City | Distance |
|---|---|---|
21778 | Rocky Ridge, MD | 4.9 mi |
21780 | Sabillasville, MD | 6.5 mi |
21775 | New Midway, MD | 6.6 mi |
21759 | Ladiesburg, MD | 6.7 mi |
21798 | Woodsboro, MD | 7.3 mi |
21702 | Frederick, MD | 7.8 mi |
21793 | Walkersville, MD | 7.9 mi |
21773 | Myersville, MD | 8.0 mi |
21727 | Emmitsburg, MD | 8.2 mi |
21757 | Keymar, MD | 8.3 mi |
Find every ZIP code within 10 miles of 21788 →
Questions about this ZIP code
Where is ZIP code 21788?
21788 is in Thurmont, Maryland, in Frederick County, part of the Washington-Arlington-Alexandria, DC-VA-MD-WV metropolitan area. Its published point location is 39.5900, -77.4139.
What county is 21788 in?
21788 lies in Frederick County.
What area code is 21788?
Thurmont uses area codes 240, 227 and 301, from NANPA's telephone records.
What time zone is 21788 in?
21788 uses America/New_York.
How many people live in 21788?
About 11,654 people live in ZIP code 21788, in 4,649 households, at 178.1 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 21788?
$98,856 a year, against $103,678 across Maryland.
What ZIP codes are near 21788?
The closest are 21778 (4.9 mi), 21780 (6.5 mi), 21775 (6.6 mi), 21759 (6.7 mi) and 21798 (7.3 mi).
Is 21788 a PO Box ZIP code?
21788 is a standard ZIP code. A normal ZIP code with street delivery.
Download or cite
Cite this page
zipcodes.pro. “21788 ZIP Code — Thurmont, Maryland (Frederick County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21788
Machine-readable version of these facts:
curl https://zipcodes.pro/zip/21788.jsonUnderlying data is public domain or openly licensed — sources, vintages and licences.