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Where 21661 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 21661 into a pocket calculator and turn it upside down: IggIZ — not quite a word, sorry.
- ➕ 21661 is a prime number. It cannot be divided by anything except 1 and itself. Its digits add up to 16, a total 1,922 other ZIP codes share.
- 💾In binary, the way a computer stores it:
101010010011101 - 🏠 Its numerical neighbours: 21660 (Ridgely, MD, 20 mi away) and 21662 (Royal Oak, MD, 26 mi away).
- 🔄 Backwards, 21661 becomes 16612, which is not a ZIP code at all.
- 👥 11 other ZIP codes are made of exactly the same digits (12166, 16261, 16621, 26161, 26611, 61126, …). The farthest-flung twin is 66112 in Kansas City, KS, 993 miles away.
- 🧭 Farther south than 50% of all ZIP codes, and farther east than 84%.
- 🎯1,191 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
- 🌏 Dig straight through the Earth from 21661 and you would come out at 39.10°S, 103.78°E — 838 miles from Perth, Australia, the nearest big city to that spot.
- ☀Longest day of the year: 14h 55m of daylight. Shortest: 9h 25m.
- 📏 At 33.0 square miles of land, 21661 is bigger than 48% of ZIP codes — room for about 25 Central Parks.
- Working out the sun…
- Checking the USGS…
Source: USGS.
People and housing
| Population | 2,613This ZIP2,613 |
|---|---|
| Households | 1,311This ZIP1,311 |
| Housing units | 1,784This ZIP1,784 |
| Median age | 58.4This ZIP58.4Maryland39.4US 38.9 |
| Median household income | $90,492This ZIP$90,492Maryland$103,678US $80,734 |
| Median home value | $283,200This ZIP$283,200Maryland$419,900US $332,700 |
| Median gross rent | $1,000This ZIP$1,000Maryland$1,705US $1,413 |
| Bachelor's degree or higher | 35.7%This ZIP35.7% |
| Mean commute | 23.6 minThis ZIP23.6 min |
| Population density | 79.2 / sq miThis ZIP79.2 / sq mi |
Business and tax activity
| Business establishments | 62This ZIP62 |
|---|---|
| Employees | 424This ZIP424 |
| Annual payroll | $14,699,000This ZIP$14,699,000 |
| Tax returns filed | 1,200This ZIP1,200 |
| Total adjusted gross income | $88,365,000This ZIP$88,365,000 |
Land area
| Land area | 33.01 sq miThis ZIP33.01 sq mi |
|---|---|
| Water area | 22.06 sq miThis ZIP22.06 sq mi |
Other place names in 21661
Census places whose land this ZIP code overlaps. The Postal Service may accept other city names in an address, too.
ZIP codes near 21661
| ZIP | City | Distance |
|---|---|---|
21656 | Price, MD | 8.0 mi |
21690 | Chestertown, MD | 8.0 mi |
21617 | Centreville, MD | 9.9 mi |
21620 | Chestertown, MD | 10.6 mi |
21638 | Grasonville, MD | 10.8 mi |
21619 | Chester, MD | 10.9 mi |
21658 | Queenstown, MD | 11.2 mi |
21056 | Gibson Island, MD | 11.7 mi |
21666 | Stevensville, MD | 12.5 mi |
21409 | Annapolis, MD | 13.1 mi |
Find every ZIP code within 10 miles of 21661 →
Questions about this ZIP code
Where is ZIP code 21661?
21661 is in Rock Hall, Maryland, in Kent County. Its published point location is 39.0961, -76.2195.
What county is 21661 in?
21661 lies in Kent County.
What area code is 21661?
Rock Hall uses area codes 667 and 410, from NANPA's telephone records.
What time zone is 21661 in?
21661 uses America/New_York.
How many people live in 21661?
About 2,613 people live in ZIP code 21661, in 1,311 households, at 79.2 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 21661?
$90,492 a year, against $103,678 across Maryland.
What ZIP codes are near 21661?
The closest are 21656 (8 mi), 21690 (8 mi), 21617 (9.9 mi), 21620 (10.6 mi) and 21638 (10.8 mi).
Is 21661 a PO Box ZIP code?
21661 is a standard ZIP code. A normal ZIP code with street delivery.
Download or cite
Cite this page
zipcodes.pro. “21661 ZIP Code — Rock Hall, Maryland (Kent County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21661
Machine-readable version of these facts:
curl https://zipcodes.pro/zip/21661.jsonUnderlying data is public domain or openly licensed — sources, vintages and licences.