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Where 21131 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 21131 into a pocket calculator and turn it upside down: IEIIZ — not quite a word, sorry.
- ➕ As a number, 21,131 = 11 × 17 × 113. Its digits add up to 8, a total 251 other ZIP codes share.
- 💾In binary, the way a computer stores it:
101001010001011 - 🏠 Its numerical neighbours: 21130 (Perryman, MD, 21 mi away) and 21132 (Pylesville, MD, 16 mi away).
- 🔄 Backwards, 21131 becomes 13112 — and that is a real ZIP code: Memphis, NY, 249 miles away.
- 👥 10 other ZIP codes are made of exactly the same digits (11213, 11231, 12131, 13112, 13121, 13211, …). The farthest-flung twin is 32111 in Candler, FL, 784 miles away.
- 🧭 Farther north than 52% of all ZIP codes, and farther east than 83%.
- 🎯1,167 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
- 🌏 Dig straight through the Earth from 21131 and you would come out at 39.50°S, 103.41°E — 870 miles from Perth, Australia, the nearest big city to that spot.
- ☀Longest day of the year: 14h 58m of daylight. Shortest: 9h 22m.
- 📏 At 21.0 square miles of land, 21131 is bigger than 38% of ZIP codes — room for about 16 Central Parks.
- Working out the sun…
- Checking the USGS…
Source: USGS.
People and housing
| Population | 7,141This ZIP7,141 |
|---|---|
| Households | 2,600This ZIP2,600 |
| Housing units | 2,658This ZIP2,658 |
| Median age | 49.4This ZIP49.4Maryland39.4US 38.9 |
| Median household income | $197,619This ZIP$197,619Maryland$103,678US $80,734 |
| Median home value | $686,000This ZIP$686,000Maryland$419,900US $332,700 |
| Bachelor's degree or higher | 73.9%This ZIP73.9% |
| Mean commute | 30.0 minThis ZIP30.0 min |
| Population density | 339.5 / sq miThis ZIP339.5 / sq mi |
Business and tax activity
| Business establishments | 215This ZIP215 |
|---|---|
| Employees | 1,746This ZIP1,746 |
| Annual payroll | $83,892,000This ZIP$83,892,000 |
| Tax returns filed | 3,780This ZIP3,780 |
| Total adjusted gross income | $894,619,000This ZIP$894,619,000 |
Land area
| Land area | 21.03 sq miThis ZIP21.03 sq mi |
|---|---|
| Water area | 1.39 sq miThis ZIP1.39 sq mi |
Other place names in 21131
Census places whose land this ZIP code overlaps. The Postal Service may accept other city names in an address, too.
ZIP codes near 21131
| ZIP | City | Distance |
|---|---|---|
21065 | Hunt Valley, MD | 3.6 mi |
21031 | Hunt Valley, MD | 3.9 mi |
21092 | Long Green, MD | 4.2 mi |
21094 | Lutherville Timonium, MD | 4.5 mi |
21111 | Monkton, MD | 4.9 mi |
21013 | Baldwin, MD | 5.3 mi |
21093 | Lutherville Timonium, MD | 5.4 mi |
21057 | Glen Arm, MD | 5.6 mi |
21030 | Cockeysville, MD | 5.9 mi |
21152 | Sparks Glencoe, MD | 6.2 mi |
Find every ZIP code within 10 miles of 21131 →
Questions about this ZIP code
Where is ZIP code 21131?
21131 is in Phoenix, Maryland, in Baltimore County, part of the Baltimore-Columbia-Towson, MD metropolitan area. Its published point location is 39.5045, -76.5892.
What county is 21131 in?
21131 lies in Baltimore County.
What area code is 21131?
Phoenix uses area codes 410, 443 and 667, from NANPA's telephone records.
What time zone is 21131 in?
21131 uses America/New_York.
How many people live in 21131?
About 7,141 people live in ZIP code 21131, in 2,600 households, at 339.5 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 21131?
$197,619 a year, against $103,678 across Maryland.
What ZIP codes are near 21131?
The closest are 21065 (3.6 mi), 21031 (3.9 mi), 21092 (4.2 mi), 21094 (4.5 mi) and 21111 (4.9 mi).
Is 21131 a PO Box ZIP code?
21131 is a standard ZIP code. A normal ZIP code with street delivery.
Download or cite
Cite this page
zipcodes.pro. “21131 ZIP Code — Phoenix, Maryland (Baltimore County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21131
Machine-readable version of these facts:
curl https://zipcodes.pro/zip/21131.jsonUnderlying data is public domain or openly licensed — sources, vintages and licences.