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Where 21155 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 21155 into a pocket calculator and turn it upside down: SSIIZ — not quite a word, sorry.
- ➕ As a number, 21,155 = 5 × 4231. Its digits add up to 14, a total 1,416 other ZIP codes share.
- 💾In binary, the way a computer stores it:
101001010100011 - 🏠 Its numerical neighbours: 21154 (Street, MD, 24 mi away) and 21156 (Upper Falls, MD, 24 mi away).
- 🔄 Backwards, 21155 becomes 55112 — and that is a real ZIP code: Saint Paul, MN, 917 miles away.
- 👥 13 other ZIP codes are made of exactly the same digits (11552, 12155, 12515, 12551, 15215, 15251, …). The farthest-flung twin is 51521 in Avoca, IA, 981 miles away.
- 🧭 Farther north than 53% of all ZIP codes, and farther east than 82%.
- 🎯1,155 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
- 🌏 Dig straight through the Earth from 21155 and you would come out at 39.57°S, 103.19°E — 883 miles from Perth, Australia, the nearest big city to that spot.
- ☀Longest day of the year: 14h 58m of daylight. Shortest: 9h 22m.
- 📏 At 22.1 square miles of land, 21155 is bigger than 39% of ZIP codes — room for about 17 Central Parks.
- Working out the sun…
- Checking the USGS…
Source: USGS.
People and housing
| Population | 3,313This ZIP3,313 |
|---|---|
| Households | 1,032This ZIP1,032 |
| Housing units | 1,229This ZIP1,229 |
| Median age | 33.7This ZIP33.7Maryland39.4US 38.9 |
| Median household income | $123,158This ZIP$123,158Maryland$103,678US $80,734 |
| Median home value | $479,500This ZIP$479,500Maryland$419,900US $332,700 |
| Median gross rent | $1,513This ZIP$1,513Maryland$1,705US $1,413 |
| Bachelor's degree or higher | 43.5%This ZIP43.5% |
| Mean commute | 30.6 minThis ZIP30.6 min |
| Population density | 149.7 / sq miThis ZIP149.7 / sq mi |
Business and tax activity
| Business establishments | 66This ZIP66 |
|---|---|
| Employees | 379This ZIP379 |
| Annual payroll | $16,147,000This ZIP$16,147,000 |
| Tax returns filed | 1,300This ZIP1,300 |
| Total adjusted gross income | $176,413,000This ZIP$176,413,000 |
Land area
| Land area | 22.13 sq miThis ZIP22.13 sq mi |
|---|---|
| Water area | 0.06 sq miThis ZIP0.06 sq mi |
Counties 21155 spans
A ZIP code is a mail route and ignores county lines. Shares are by overlapping land area.
| County | Share of this ZIP |
|---|---|
| Baltimore County | 89.1% |
| Carroll County | 10.9% |
ZIP codes near 21155
| ZIP | City | Distance |
|---|---|---|
21020 | Boring, MD | 3.6 mi |
21074 | Hampstead, MD | 3.8 mi |
21023 | Butler, MD | 4.9 mi |
21071 | Glyndon, MD | 6.2 mi |
21152 | Sparks Glencoe, MD | 6.5 mi |
21030 | Cockeysville, MD | 7.0 mi |
21048 | Finksburg, MD | 8.1 mi |
21102 | Manchester, MD | 8.5 mi |
21120 | Parkton, MD | 8.6 mi |
21136 | Reisterstown, MD | 9.5 mi |
Find every ZIP code within 10 miles of 21155 →
Questions about this ZIP code
Where is ZIP code 21155?
21155 is in Upperco, Maryland, in Baltimore County, part of the Baltimore-Columbia-Towson, MD metropolitan area. Its published point location is 39.5736, -76.8061.
What county is 21155 in?
21155 spans 2 counties: Baltimore County and Carroll County. Most of it falls in Baltimore County, measured by overlapping land area — the county holding the most land in a ZIP code is not always the one holding the most residents.
What area code is 21155?
Upperco uses area codes 443, 667 and 410, from NANPA's telephone records.
What time zone is 21155 in?
21155 uses America/New_York.
How many people live in 21155?
About 3,313 people live in ZIP code 21155, in 1,032 households, at 149.7 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 21155?
$123,158 a year, against $103,678 across Maryland.
What ZIP codes are near 21155?
The closest are 21020 (3.6 mi), 21074 (3.8 mi), 21023 (4.9 mi), 21071 (6.2 mi) and 21152 (6.5 mi).
Is 21155 a PO Box ZIP code?
21155 is a standard ZIP code. A normal ZIP code with street delivery.
Download or cite
Cite this page
zipcodes.pro. “21155 ZIP Code — Upperco, Maryland (Baltimore County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21155
Machine-readable version of these facts:
curl https://zipcodes.pro/zip/21155.jsonUnderlying data is public domain or openly licensed — sources, vintages and licences.