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zipcodes.pro — ZIP/21757

21757

ZIP 21757 is Keymar, Maryland, mostly in Carroll County; Eastern time.

Type
Standard
Time zone
America/New_York
County
Carroll +1 more
Population
2,671
Coordinates
39.5939, -77.2581
☼ Live from 21757 — Keymar, MD

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Local time: —

Where 21757 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.

★ Weird and wonderful facts about 21757
  • 🔢 Type 21757 into a pocket calculator and turn it upside down: LSLIZ — not quite a word, sorry.
  • ➕ 21757 is a prime number. It cannot be divided by anything except 1 and itself. Its digits add up to 22, a total 2,607 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 101010011111101
  • 🏠 Its numerical neighbours: 21756 (Keedysville, MD, 25 mi away) and 21758 (Knoxville, MD, 27 mi away).
  • 🔄 Backwards, 21757 becomes 75712 — and that is a real ZIP code: Tyler, TX, 1,121 miles away.
  • 👥 37 other ZIP codes are made of exactly the same digits (12577, 12775, 15277, 15727, 15772, 17257, …). The farthest-flung twin is 77512 in Alvin, TX, 1,238 miles away.
  • 🧭 Farther north than 53% of all ZIP codes, and farther east than 80%.
  • 🎯1,131 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 21757 and you would come out at 39.59°S, 102.74°E — 904 miles from Perth, Australia, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 58m of daylight. Shortest: 9h 22m.
  • 📏 At 35.2 square miles of land, 21757 is bigger than 50% of ZIP codes — room for about 27 Central Parks.
🌙 The sky over 21757 today
  • Working out the sun…
🌋 Shake report
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Source: USGS.

People and housing

Population2,671This ZIP2,671
Households1,018This ZIP1,018
Housing units1,072This ZIP1,072
Median age37.8This ZIP37.8Maryland39.4US 38.9
Median household income$100,500This ZIP$100,500Maryland$103,678US $80,734
Median home value$466,100This ZIP$466,100Maryland$419,900US $332,700
Median gross rent$1,408This ZIP$1,408Maryland$1,705US $1,413
Bachelor's degree or higher29.5%This ZIP29.5%
Mean commute31.4 minThis ZIP31.4 min
Population density75.9 / sq miThis ZIP75.9 / sq mi

Business and tax activity

Business establishments64This ZIP64
Employees457This ZIP457
Annual payroll$24,356,000This ZIP$24,356,000
Tax returns filed1,400This ZIP1,400
Total adjusted gross income$113,847,000This ZIP$113,847,000

Land area

Land area35.17 sq miThis ZIP35.17 sq mi
Water area0.09 sq miThis ZIP0.09 sq mi

Counties 21757 spans

A ZIP code is a mail route and ignores county lines. Shares are by overlapping land area.

CountyShare of this ZIP
Carroll County 52.3%
Frederick County 47.6%

ZIP codes near 21757

ZIPCityDistance
21759 Ladiesburg, MD 2.4 mi
21775 New Midway, MD 2.8 mi
21778 Rocky Ridge, MD 4.0 mi
21798 Woodsboro, MD 4.3 mi
21791 Union Bridge, MD 5.6 mi
21787 Taneytown, MD 7.4 mi
21727 Emmitsburg, MD 7.6 mi
21762 Libertytown, MD 7.8 mi
21788 Thurmont, MD 8.3 mi
21793 Walkersville, MD 8.6 mi

Find every ZIP code within 10 miles of 21757 →

Questions about this ZIP code

Where is ZIP code 21757?

21757 is in Keymar, Maryland, in Carroll County, part of the Baltimore-Columbia-Towson, MD metropolitan area. Its published point location is 39.5939, -77.2581.

What county is 21757 in?

21757 spans 2 counties: Carroll County and Frederick County. Most of it falls in Carroll 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 time zone is 21757 in?

21757 uses America/New_York.

How many people live in 21757?

About 2,671 people live in ZIP code 21757, in 1,018 households, at 75.9 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 21757?

$100,500 a year, against $103,678 across Maryland.

What ZIP codes are near 21757?

The closest are 21759 (2.4 mi), 21775 (2.8 mi), 21778 (4 mi), 21798 (4.3 mi) and 21791 (5.6 mi).

Is 21757 a PO Box ZIP code?

21757 is a standard ZIP code. A normal ZIP code with street delivery.

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Cite this page

zipcodes.pro. “21757 ZIP Code — Keymar, Maryland (Carroll County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21757

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