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ZIP stands for Zone Improvement Plan. The codes went live on July 1, 1963.The lowest ZIP code is 00501 — the IRS in Holtsville, New York.The highest ZIP code is 99950, in Ketchikan, Alaska.Type 07734 into a calculator and turn it upside down: hELLO. It is Keansburg, New Jersey.12345 belongs to one company: General Electric in Schenectady, New York.The first digit is a region: 0 is New England and New Jersey, 9 is the West Coast, Alaska and Hawaii.Mr. ZIP, the cartoon mailman, was the mascot that sold the idea to America.ZIP+4 arrived in 1983 and can narrow a ZIP down to one side of one block.A ZIP code is a mail route, not a place: plenty of them cross county and even state lines.Play ZIP Hunt: guess the secret ZIP code of the day in six tries.
zipcodes.pro — ZIP/21701

21701

ZIP 21701 is in Frederick, Maryland, in Frederick County; area codes 240, 301 and 227; Eastern time. Frederick has 6 ZIP codes; the others are 21702, 21703, 21704, 21705 and 21709.

Type
Standard
Time zone
America/New_York
County
Frederick
Population
43,048
Coordinates
39.4436, -77.3329
☼ Live from 21701 — Frederick, MD

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Local time: —

Where 21701 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 21701
  • 🔢 Type 21701 into a pocket calculator and turn it upside down: IOLIZ — not quite a word, sorry.
  • ➕ 21701 is a prime number. It cannot be divided by anything except 1 and itself. Its digits add up to 11, a total 714 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 101010011000101
  • 🏠 Its numerical neighbours: 21690 (Chestertown, MD, 72 mi away) and 21702 (Frederick, MD, 6 mi away).
  • 🔄 Backwards, 21701 becomes 10712, which is not a ZIP code at all.
  • 👥 40 other ZIP codes are made of exactly the same digits (01721, 02117, 02171, 07112, 10172, 10271, …). The farthest-flung twin is 71102 in Shreveport, LA, 1,030 miles away.
  • 🧭 Farther north than 52% of all ZIP codes, and farther east than 80%.
  • 🎯1,128 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 21701 and you would come out at 39.44°S, 102.67°E — 902 miles from Perth, Australia, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 57m of daylight. Shortest: 9h 23m.
  • 📏 At 39.7 square miles of land, 21701 is bigger than 53% of ZIP codes — room for about 30 Central Parks.
🌙 The sky over 21701 today
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🌋 Shake report
  • Checking the USGS…

Source: USGS.

People and housing

Population43,048This ZIP43,048
Households18,651This ZIP18,651
Housing units19,513This ZIP19,513
Median age39.6This ZIP39.6Maryland39.4US 38.9
Median household income$106,577This ZIP$106,577Maryland$103,678US $80,734
Median home value$435,000This ZIP$435,000Maryland$419,900US $332,700
Median gross rent$1,672This ZIP$1,672Maryland$1,705US $1,413
Bachelor's degree or higher50.1%This ZIP50.1%
Mean commute28.5 minThis ZIP28.5 min
Population density1,084.3 / sq miThis ZIP1,084.3 / sq mi

Business and tax activity

Business establishments1,616This ZIP1,616
Employees25,929This ZIP25,929
Annual payroll$1,472,706,000This ZIP$1,472,706,000
Tax returns filed21,520This ZIP21,520
Total adjusted gross income$2,031,879,000This ZIP$2,031,879,000

Land area

Land area39.70 sq miThis ZIP39.70 sq mi
Water area0.59 sq miThis ZIP0.59 sq mi

Other place names in 21701

Census places whose land this ZIP code overlaps. The Postal Service may accept other city names in an address, too.

ZIP codes near 21701

ZIPCityDistance
21793 Walkersville, MD 3.2 mi
21709 Frederick, MD 3.6 mi
21774 New Market, MD 3.9 mi
21705 Frederick, MD 4.8 mi
21762 Libertytown, MD 5.2 mi
21702 Frederick, MD 6.4 mi
21704 Frederick, MD 6.5 mi
21798 Woodsboro, MD 6.8 mi
21770 Monrovia, MD 7.6 mi
21754 Ijamsville, MD 7.8 mi

Find every ZIP code within 10 miles of 21701 →

Questions about this ZIP code

Where is ZIP code 21701?

21701 is in Frederick, Maryland, in Frederick County, part of the Washington-Arlington-Alexandria, DC-VA-MD-WV metropolitan area. Its published point location is 39.4436, -77.3329.

What county is 21701 in?

21701 lies in Frederick County.

What area code is 21701?

Frederick uses area codes 240, 301 and 227, from NANPA's telephone records.

What time zone is 21701 in?

21701 uses America/New_York.

How many people live in 21701?

About 43,048 people live in ZIP code 21701, in 18,651 households, at 1,084.3 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 21701?

$106,577 a year, against $103,678 across Maryland.

What ZIP codes are near 21701?

The closest are 21793 (3.2 mi), 21709 (3.6 mi), 21774 (3.9 mi), 21705 (4.8 mi) and 21762 (5.2 mi).

Is 21701 a PO Box ZIP code?

21701 is a standard ZIP code. A normal ZIP code with street delivery.

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Cite this page

zipcodes.pro. “21701 ZIP Code — Frederick, Maryland (Frederick County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21701

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