21720

ZIP 21720 is Cavetown, Maryland, in Washington County; area codes 240, 227 and 301; Eastern time.

Type: No street area
Time zone: America/New_York
County: Washington
Metro area: Hagerstown-Martinsburg, MD-WV
Coordinates: 39.6473, -77.5842

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 21783, whose figures describe that area — not this ZIP code.

☼ Live from 21720 — Cavetown, MD

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Where 21720 is

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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 21720

🔢 Type 21720 into a pocket calculator and turn it upside down: OZLIZ — not quite a word, sorry.
➕ As a number, 21,720 = 2 × 2 × 2 × 3 × 5 × 181. Its digits add up to 12, a total 940 other ZIP codes share.
💾In binary, the way a computer stores it: 101010011011000
🏠 Its numerical neighbours: 21719 (Cascade, MD, 6 mi away) and 21721 (Chewsville, MD, 3 mi away).
🔄 Backwards, 21720 becomes 02712 — and that is a real ZIP code: Chartley, MA, 368 miles away.
👥 37 other ZIP codes are made of exactly the same digits (01227, 02127, 02217, 02712, 02721, 10272, …). The farthest-flung twin is 70122 in New Orleans, LA, 970 miles away.
🧭 Farther north than 53% of all ZIP codes, and farther east than 80%.
🎯1,113 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
🌏 Dig straight through the Earth from 21720 and you would come out at 39.65°S, 102.42°E — 921 miles from Perth, Australia, the nearest big city to that spot.
☀Longest day of the year: 14h 59m of daylight. Shortest: 9h 22m.

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Source: USGS.

Business and tax activity

Business establishments	7This ZIP7
Employees	194This ZIP194
Annual payroll	$13,545,000This ZIP$13,545,000

Land area

ZIP codes near 21720

ZIP	City	Distance
`21783`	Smithsburg, MD	1.7 mi
`21721`	Chewsville, MD	2.8 mi
`21742`	Hagerstown, MD	4.2 mi
`21719`	Cascade, MD	6.0 mi
`21780`	Sabillasville, MD	6.2 mi
`17250`	Rouzerville, PA	7.0 mi
`21734`	Funkstown, MD	7.0 mi
`21741`	Hagerstown, MD	7.2 mi
`21747`	Hagerstown, MD	7.2 mi
`21749`	Hagerstown, MD	7.2 mi

Find every ZIP code within 10 miles of 21720 →

Questions about this ZIP code

Where is ZIP code 21720?

21720 is in Cavetown, Maryland, in Washington County, part of the Hagerstown-Martinsburg, MD-WV metropolitan area. Its published point location is 39.6473, -77.5842.

What county is 21720 in?

21720 lies in Washington County.

What area code is 21720?

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

What time zone is 21720 in?

21720 uses America/New_York.

What ZIP codes are near 21720?

The closest are 21783 (1.7 mi), 21721 (2.8 mi), 21742 (4.2 mi), 21719 (6 mi) and 21780 (6.2 mi).

Is 21720 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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Cite this page

zipcodes.pro. “21720 ZIP Code — Cavetown, Maryland (Washington County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21720

Machine-readable version of these facts:

curl https://zipcodes.pro/zip/21720.json

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