Every ZIP code in the United States, with weather, radar, trivia and the numbers behind it. Five digits since 1963!

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/21404

21404

ZIP 21404 is in Annapolis, Maryland, in Anne Arundel County; area codes 443, 410 and 667; Eastern time. Annapolis has 8 ZIP codes in all.

Type
No street area
Time zone
America/New_York
County
Anne Arundel
Coordinates
38.9784, -76.4922

The Census map gives this ZIP code no delivery area of its own, which usually means it serves post office boxes, a single organization or a post office rather than streets of homes.

This ZIP code has no Census tabulation area of its own. Its point falls inside ZCTA 21401, whose figures describe that area — not this ZIP code.

☼ Live from 21404 — Annapolis, MD

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Where 21404 is

This ZIP code has no Census tabulation area, so there is no boundary to draw — the marker is its published point location.

★ Weird and wonderful facts about 21404
  • 🔢 Type 21404 into a pocket calculator and turn it upside down: hOhIZ — not quite a word, sorry.
  • ➕ As a number, 21,404 = 2 × 2 × 5351. Its digits add up to 11, a total 714 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 101001110011100
  • 🏠 Its numerical neighbours: 21403 (Annapolis, MD, 3 mi away) and 21405 (Annapolis, MD, 5 mi away).
  • 🔄 Backwards, 21404 becomes 40412, which is not a ZIP code at all.
  • 👥 36 other ZIP codes are made of exactly the same digits (01244, 02144, 04124, 04241, 04412, 04421, …). The farthest-flung twin is 42041 in Fulton, KY, 696 miles away.
  • 🧭 Farther south than 51% of all ZIP codes, and farther east than 83%.
  • 🎯1,178 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 21404 and you would come out at 38.98°S, 103.51°E — 847 miles from Perth, Australia, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 54m of daylight. Shortest: 9h 26m.
🌙 The sky over 21404 today
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🌋 Shake report
  • Checking the USGS…

Source: USGS.

Business and tax activity

Business establishments6This ZIP6
Employees166This ZIP166
Annual payroll$5,019,000This ZIP$5,019,000

Land area

ZIP codes near 21404

ZIPCityDistance
21402 Annapolis, MD 1.3 mi
21403 Annapolis, MD 2.5 mi
21401 Annapolis, MD 3.3 mi
21409 Annapolis, MD 3.8 mi
21405 Annapolis, MD 4.6 mi
21012 Arnold, MD 4.7 mi
21037 Edgewater, MD 4.9 mi
21140 Riva, MD 5.4 mi
21062 Glen Burnie, MD 5.5 mi
21123 Pasadena, MD 5.5 mi

Find every ZIP code within 10 miles of 21404 →

Questions about this ZIP code

Where is ZIP code 21404?

21404 is in Annapolis, Maryland, in Anne Arundel County, part of the Baltimore-Columbia-Towson, MD metropolitan area. Its published point location is 38.9784, -76.4922.

What county is 21404 in?

21404 lies in Anne Arundel County.

What area code is 21404?

Annapolis uses area codes 443, 410 and 667, from NANPA's telephone records.

What time zone is 21404 in?

21404 uses America/New_York.

What ZIP codes are near 21404?

The closest are 21402 (1.3 mi), 21403 (2.5 mi), 21401 (3.3 mi), 21409 (3.8 mi) and 21405 (4.6 mi).

Is 21404 a PO Box ZIP code?

Possibly. The Census map gives this ZIP code no delivery area of its own, which usually means it serves post office boxes, a single organization or a post office rather than streets of homes.

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zipcodes.pro. “21404 ZIP Code — Annapolis, Maryland (Anne Arundel County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21404

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