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Where 21111 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 21111 into a pocket calculator and turn it upside down: IIIIZ — not quite a word, sorry.
- ➕ As a number, 21,111 = 3 × 31 × 227. Its digits add up to 6, a total 90 other ZIP codes share.
- 💾In binary, the way a computer stores it:
101001001110111 - 🏠 Its numerical neighbours: 21108 (Millersville, MD, 34 mi away) and 21113 (Odenton, MD, 36 mi away).
- 🔄 Backwards, 21111 becomes 11112, which is not a ZIP code at all.
- 👥 1 other ZIP code is made of exactly the same digits (11211). The farthest-flung twin is 11211 in Brooklyn, NY, 160 miles away.
- 🧭 Farther north than 53% of all ZIP codes, and farther east than 83%.
- 🎯1,166 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
- 🌏 Dig straight through the Earth from 21111 and you would come out at 39.58°S, 103.41°E — 873 miles from Perth, Australia, the nearest big city to that spot.
- ☀Longest day of the year: 14h 58m of daylight. Shortest: 9h 22m.
- 📏 At 35.3 square miles of land, 21111 is bigger than 50% of ZIP codes — room for about 27 Central Parks.
- Working out the sun…
- Checking the USGS…
Source: USGS.
People and housing
| Population | 4,714This ZIP4,714 |
|---|---|
| Households | 1,908This ZIP1,908 |
| Housing units | 1,939This ZIP1,939 |
| Median age | 48.7This ZIP48.7Maryland39.4US 38.9 |
| Median household income | $136,304This ZIP$136,304Maryland$103,678US $80,734 |
| Median home value | $607,200This ZIP$607,200Maryland$419,900US $332,700 |
| Median gross rent | $1,359This ZIP$1,359Maryland$1,705US $1,413 |
| Bachelor's degree or higher | 63.7%This ZIP63.7% |
| Mean commute | 31.9 minThis ZIP31.9 min |
| Population density | 133.4 / sq miThis ZIP133.4 / sq mi |
Business and tax activity
| Business establishments | 119This ZIP119 |
|---|---|
| Employees | 865This ZIP865 |
| Annual payroll | $40,964,000This ZIP$40,964,000 |
| Tax returns filed | 2,520This ZIP2,520 |
| Total adjusted gross income | $597,837,000This ZIP$597,837,000 |
Land area
| Land area | 35.35 sq miThis ZIP35.35 sq mi |
|---|---|
| Water area | 0.20 sq miThis ZIP0.20 sq mi |
Counties 21111 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 | 76.7% |
| Harford County | 23.3% |
ZIP codes near 21111
| ZIP | City | Distance |
|---|---|---|
21131 | Phoenix, MD | 4.9 mi |
21152 | Sparks Glencoe, MD | 5.3 mi |
21161 | White Hall, MD | 6.0 mi |
21120 | Parkton, MD | 6.7 mi |
21013 | Baldwin, MD | 6.9 mi |
21065 | Hunt Valley, MD | 6.9 mi |
21084 | Jarrettsville, MD | 7.1 mi |
21031 | Hunt Valley, MD | 7.1 mi |
21030 | Cockeysville, MD | 7.1 mi |
21092 | Long Green, MD | 7.9 mi |
Find every ZIP code within 10 miles of 21111 →
Questions about this ZIP code
Where is ZIP code 21111?
21111 is in Monkton, Maryland, in Baltimore County, part of the Baltimore-Columbia-Towson, MD metropolitan area. Its published point location is 39.5755, -76.5897.
What county is 21111 in?
21111 spans 2 counties: Baltimore County and Harford 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 21111?
Monkton uses area codes 443, 410 and 667, from NANPA's telephone records.
What time zone is 21111 in?
21111 uses America/New_York.
How many people live in 21111?
About 4,714 people live in ZIP code 21111, in 1,908 households, at 133.4 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 21111?
$136,304 a year, against $103,678 across Maryland.
What ZIP codes are near 21111?
The closest are 21131 (4.9 mi), 21152 (5.3 mi), 21161 (6 mi), 21120 (6.7 mi) and 21013 (6.9 mi).
Is 21111 a PO Box ZIP code?
21111 is a standard ZIP code. A normal ZIP code with street delivery.
Download or cite
Cite this page
zipcodes.pro. “21111 ZIP Code — Monkton, Maryland (Baltimore County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21111
Machine-readable version of these facts:
curl https://zipcodes.pro/zip/21111.jsonUnderlying data is public domain or openly licensed — sources, vintages and licences.