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Where 21057 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 21057 into a pocket calculator and turn it upside down: LSOIZ — not quite a word, sorry.
- ➕ As a number, 21,057 = 3 × 7019. Its digits add up to 15, a total 1,657 other ZIP codes share.
- 💾In binary, the way a computer stores it:
101001001000001 - 🏠 Its numerical neighbours: 21056 (Gibson Island, MD, 26 mi away) and 21060 (Glen Burnie, MD, 19 mi away).
- 🔄 Backwards, 21057 becomes 75012, which is not a ZIP code at all.
- 👥 65 other ZIP codes are made of exactly the same digits (01257, 01527, 01752, 02571, 02715, 07512, …). The farthest-flung twin is 75102 in Barry, TX, 1,234 miles away.
- 🧭 Farther north than 52% of all ZIP codes, and farther east than 83%.
- 🎯1,171 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
- 🌏 Dig straight through the Earth from 21057 and you would come out at 39.45°S, 103.49°E — 865 miles from Perth, Australia, the nearest big city to that spot.
- ☀Longest day of the year: 14h 57m of daylight. Shortest: 9h 23m.
- 📏 At 15.9 square miles of land, 21057 is bigger than 34% of ZIP codes — room for about 12 Central Parks.
- Working out the sun…
- Checking the USGS…
Source: USGS.
People and housing
| Population | 4,386This ZIP4,386 |
|---|---|
| Households | 1,545This ZIP1,545 |
| Housing units | 1,603This ZIP1,603 |
| Median age | 41.3This ZIP41.3Maryland39.4US 38.9 |
| Median household income | $145,924This ZIP$145,924Maryland$103,678US $80,734 |
| Median home value | $623,200This ZIP$623,200Maryland$419,900US $332,700 |
| Median gross rent | $1,746This ZIP$1,746Maryland$1,705US $1,413 |
| Bachelor's degree or higher | 54.0%This ZIP54.0% |
| Mean commute | 32.7 minThis ZIP32.7 min |
| Population density | 276.0 / sq miThis ZIP276.0 / sq mi |
Business and tax activity
| Business establishments | 110This ZIP110 |
|---|---|
| Employees | 879This ZIP879 |
| Annual payroll | $51,451,000This ZIP$51,451,000 |
| Tax returns filed | 2,100This ZIP2,100 |
| Total adjusted gross income | $294,044,000This ZIP$294,044,000 |
Land area
| Land area | 15.89 sq miThis ZIP15.89 sq mi |
|---|---|
| Water area | 0.44 sq miThis ZIP0.44 sq mi |
Other place names in 21057
Census places whose land this ZIP code overlaps. The Postal Service may accept other city names in an address, too.
ZIP codes near 21057
| ZIP | City | Distance |
|---|---|---|
21092 | Long Green, MD | 1.8 mi |
21082 | Hydes, MD | 2.9 mi |
21051 | Fork, MD | 3.4 mi |
21234 | Parkville, MD | 4.0 mi |
21286 | Towson, MD | 4.1 mi |
21094 | Lutherville Timonium, MD | 4.3 mi |
21236 | Nottingham, MD | 4.5 mi |
21013 | Baldwin, MD | 4.5 mi |
21128 | Perry Hall, MD | 4.6 mi |
21087 | Kingsville, MD | 5.3 mi |
Find every ZIP code within 10 miles of 21057 →
Questions about this ZIP code
Where is ZIP code 21057?
21057 is in Glen Arm, Maryland, in Baltimore County, part of the Baltimore-Columbia-Towson, MD metropolitan area. Its published point location is 39.4487, -76.5125.
What county is 21057 in?
21057 lies in Baltimore County.
What area code is 21057?
Glen Arm uses area codes 410, 443 and 667, from NANPA's telephone records.
What time zone is 21057 in?
21057 uses America/New_York.
How many people live in 21057?
About 4,386 people live in ZIP code 21057, in 1,545 households, at 276.0 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 21057?
$145,924 a year, against $103,678 across Maryland.
What ZIP codes are near 21057?
The closest are 21092 (1.8 mi), 21082 (2.9 mi), 21051 (3.4 mi), 21234 (4 mi) and 21286 (4.1 mi).
Is 21057 a PO Box ZIP code?
21057 is a standard ZIP code. A normal ZIP code with street delivery.
Download or cite
Cite this page
zipcodes.pro. “21057 ZIP Code — Glen Arm, Maryland (Baltimore County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21057
Machine-readable version of these facts:
curl https://zipcodes.pro/zip/21057.jsonUnderlying data is public domain or openly licensed — sources, vintages and licences.