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/20830

20830

ZIP 20830 is in Olney, Maryland, in Montgomery County; area codes 240, 301 and 227; Eastern time. Olney has 2 ZIP codes; the other is 20832.

Type
No street area
Time zone
America/New_York
County
Montgomery
Coordinates
39.1552, -77.0667

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 20832, whose figures describe that area — not this ZIP code.

☼ Live from 20830 — Olney, MD

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Where 20830 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 20830
  • 🔢 Type 20830 into a pocket calculator and turn it upside down: OEBOZ — not quite a word, sorry.
  • ➕ As a number, 20,830 = 2 × 5 × 2083. Its digits add up to 13, a total 1,179 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 101000101011110
  • 🏠 Its numerical neighbours: 20827 (Bethesda, MD, 8 mi away) and 20832 (Olney, MD, 1 mi away).
  • 🔄 Backwards, 20830 becomes 03802 — and that is a real ZIP code: Portsmouth, NH, 425 miles away.
  • 👥 28 other ZIP codes are made of exactly the same digits (00823, 02038, 02830, 03082, 03280, 03802, …). The farthest-flung twin is 83002 in Jackson, WY, 1,762 miles away.
  • 🧭 Farther north than 50% of all ZIP codes, and farther east than 81%.
  • 🎯1,145 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 20830 and you would come out at 39.16°S, 102.93°E — 879 miles from Perth, Australia, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 55m of daylight. Shortest: 9h 25m.
🌙 The sky over 20830 today
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Source: USGS.

Business and tax activity

Business establishments5This ZIP5
Employees76This ZIP76
Annual payroll$9,524,000This ZIP$9,524,000

Land area

ZIP codes near 20830

ZIPCityDistance
20832 Olney, MD 0.7 mi
20860 Sandy Spring, MD 1.7 mi
20862 Brinklow, MD 3.2 mi
20861 Ashton, MD 3.7 mi
20855 Derwood, MD 3.7 mi
20833 Brookeville, MD 3.8 mi
20853 Rockville, MD 4.0 mi
20906 Silver Spring, MD 4.7 mi
20905 Silver Spring, MD 5.3 mi
20879 Gaithersburg, MD 5.3 mi

Find every ZIP code within 10 miles of 20830 →

Questions about this ZIP code

Where is ZIP code 20830?

20830 is in Olney, Maryland, in Montgomery County, part of the Washington-Arlington-Alexandria, DC-VA-MD-WV metropolitan area. Its published point location is 39.1552, -77.0667.

What county is 20830 in?

20830 lies in Montgomery County.

What area code is 20830?

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

What time zone is 20830 in?

20830 uses America/New_York.

What ZIP codes are near 20830?

The closest are 20832 (0.7 mi), 20860 (1.7 mi), 20862 (3.2 mi), 20861 (3.7 mi) and 20855 (3.7 mi).

Is 20830 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. “20830 ZIP Code — Olney, Maryland (Montgomery County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/20830

Machine-readable version of these facts:

curl https://zipcodes.pro/zip/20830.json

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