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Where 21001 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 21001 into a pocket calculator and turn it upside down: IOOIZ — not quite a word, sorry.
- ➕ 21001 is a prime number. It cannot be divided by anything except 1 and itself. Its digits add up to 4, a total 27 other ZIP codes share.
- 💾In binary, the way a computer stores it:
101001000001001 - 🏠 Its numerical neighbours: 20997 (Silver Spring, MD, 57 mi away) and 21005 (Aberdeen Proving Ground, MD, 5 mi away).
- 🔄 Backwards, 21001 becomes 10012 — and that is a real ZIP code: New York, NY, 144 miles away.
- 👥 16 other ZIP codes are made of exactly the same digits (01012, 01021, 01102, 01201, 02110, 10012, …). The farthest-flung twin is 02110 in Boston, MA, 333 miles away.
- 🧭 Farther north than 52% of all ZIP codes, and farther east than 84%.
- 🎯1,187 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
- 🌏 Dig straight through the Earth from 21001 and you would come out at 39.50°S, 103.80°E — 853 miles from Perth, Australia, the nearest big city to that spot.
- ☀Longest day of the year: 14h 58m of daylight. Shortest: 9h 22m.
- 📏 At 30.0 square miles of land, 21001 is bigger than 46% of ZIP codes — room for about 23 Central Parks.
- Working out the sun…
- Checking the USGS…
Source: USGS.
People and housing
| Population | 27,168This ZIP27,168 |
|---|---|
| Households | 11,204This ZIP11,204 |
| Housing units | 11,610This ZIP11,610 |
| Median age | 37.7This ZIP37.7Maryland39.4US 38.9 |
| Median household income | $83,238This ZIP$83,238Maryland$103,678US $80,734 |
| Median home value | $285,800This ZIP$285,800Maryland$419,900US $332,700 |
| Median gross rent | $1,442This ZIP$1,442Maryland$1,705US $1,413 |
| Bachelor's degree or higher | 28.2%This ZIP28.2% |
| Mean commute | 29.1 minThis ZIP29.1 min |
| Population density | 906.8 / sq miThis ZIP906.8 / sq mi |
Business and tax activity
| Business establishments | 551This ZIP551 |
|---|---|
| Employees | 11,492This ZIP11,492 |
| Annual payroll | $637,426,000This ZIP$637,426,000 |
| Tax returns filed | 13,270This ZIP13,270 |
| Total adjusted gross income | $899,576,000This ZIP$899,576,000 |
Land area
| Land area | 29.96 sq miThis ZIP29.96 sq mi |
|---|---|
| Water area | 1.48 sq miThis ZIP1.48 sq mi |
Other place names in 21001
Census places whose land this ZIP code overlaps. The Postal Service may accept other city names in an address, too.
ZIP codes near 21001
| ZIP | City | Distance |
|---|---|---|
21130 | Perryman, MD | 2.1 mi |
21017 | Belcamp, MD | 2.7 mi |
21078 | Havre De Grace, MD | 4.9 mi |
21028 | Churchville, MD | 5.0 mi |
21009 | Abingdon, MD | 5.0 mi |
21005 | Aberdeen Proving Ground, MD | 5.3 mi |
21015 | Bel Air, MD | 5.6 mi |
21040 | Edgewood, MD | 6.8 mi |
21902 | Perry Point, MD | 8.0 mi |
21014 | Bel Air, MD | 8.3 mi |
Find every ZIP code within 10 miles of 21001 →
Questions about this ZIP code
Where is ZIP code 21001?
21001 is in Aberdeen, Maryland, in Harford County, part of the Baltimore-Columbia-Towson, MD metropolitan area. Its published point location is 39.5045, -76.2010.
What county is 21001 in?
21001 lies in Harford County.
What area code is 21001?
Aberdeen uses area codes 667, 443 and 410, from NANPA's telephone records.
What time zone is 21001 in?
21001 uses America/New_York.
How many people live in 21001?
About 27,168 people live in ZIP code 21001, in 11,204 households, at 906.8 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 21001?
$83,238 a year, against $103,678 across Maryland.
What ZIP codes are near 21001?
The closest are 21130 (2.1 mi), 21017 (2.7 mi), 21078 (4.9 mi), 21028 (5 mi) and 21009 (5 mi).
Is 21001 a PO Box ZIP code?
21001 is a standard ZIP code. A normal ZIP code with street delivery.
Download or cite
Cite this page
zipcodes.pro. “21001 ZIP Code — Aberdeen, Maryland (Harford County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21001
Machine-readable version of these facts:
curl https://zipcodes.pro/zip/21001.jsonUnderlying data is public domain or openly licensed — sources, vintages and licences.