21721

ZIP 21721 is Chewsville, Maryland, in Washington County; area codes 240, 301 and 227; Eastern time.

Type: No street area
Time zone: America/New_York
County: Washington
Metro area: Hagerstown-Martinsburg, MD-WV
Coordinates: 39.6425, -77.6372

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 21721 — Chewsville, MD

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Where 21721 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 21721

🔢 Type 21721 into a pocket calculator and turn it upside down: IZLIZ — not quite a word, sorry.
➕ As a number, 21,721 = 7 × 29 × 107. Its digits add up to 13, a total 1,179 other ZIP codes share.
💾In binary, the way a computer stores it: 101010011011001
🏠 Its numerical neighbours: 21720 (Cavetown, MD, 3 mi away) and 21722 (Clear Spring, MD, 15 mi away).
🔄 Backwards, 21721 becomes 12712, which is not a ZIP code at all.
👥 13 other ZIP codes are made of exactly the same digits (11722, 12172, 12721, 17122, 17212, 17221, …). The farthest-flung twin is 71212 in Monroe, LA, 942 miles away.
🧭 Farther north than 53% of all ZIP codes, and farther east than 79%.
🎯1,110 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
🌏 Dig straight through the Earth from 21721 and you would come out at 39.64°S, 102.36°E — 923 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.

Land area

ZIP codes near 21721

ZIP	City	Distance
`21742`	Hagerstown, MD	2.6 mi
`21720`	Cavetown, MD	2.8 mi
`21734`	Funkstown, MD	4.4 mi
`21741`	Hagerstown, MD	4.4 mi
`21747`	Hagerstown, MD	4.4 mi
`21749`	Hagerstown, MD	4.4 mi
`21783`	Smithsburg, MD	4.5 mi
`21740`	Hagerstown, MD	5.7 mi
`21746`	Hagerstown, MD	6.7 mi
`21767`	Maugansville, MD	7.0 mi

Find every ZIP code within 10 miles of 21721 →

Questions about this ZIP code

Where is ZIP code 21721?

21721 is in Chewsville, Maryland, in Washington County, part of the Hagerstown-Martinsburg, MD-WV metropolitan area. Its published point location is 39.6425, -77.6372.

What county is 21721 in?

21721 lies in Washington County.

What area code is 21721?

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

What time zone is 21721 in?

21721 uses America/New_York.

What ZIP codes are near 21721?

The closest are 21742 (2.6 mi), 21720 (2.8 mi), 21734 (4.4 mi), 21741 (4.4 mi) and 21747 (4.4 mi).

Is 21721 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. “21721 ZIP Code — Chewsville, Maryland (Washington County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21721

Machine-readable version of these facts:

curl https://zipcodes.pro/zip/21721.json

Underlying data is public domain or openly licensed — sources, vintages and licences.