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/20899

20899

ZIP 20899 is in Gaithersburg, Maryland, in Montgomery County; area codes 240, 301 and 227; Eastern time. Gaithersburg has 9 ZIP codes in all.

Type
Standard
Time zone
America/New_York
County
Montgomery
Population
57
Coordinates
39.1444, -77.2162
☼ Live from 20899 — Gaithersburg, MD

Weather right now

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Local time: —

Where 20899 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 20899
  • 🔢 Type 20899 into a pocket calculator and turn it upside down: GGBOZ — not quite a word, sorry.
  • ➕ 20899 is a prime number. It cannot be divided by anything except 1 and itself. Its digits add up to 28, a total 1,520 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 101000110100011
  • 🏠 Its numerical neighbours: 20898 (Gaithersburg, MD, 0 mi away) and 20901 (Silver Spring, MD, 14 mi away).
  • 🔄 Backwards, 20899 becomes 99802 — and that is a real ZIP code: Juneau, AK, 2,814 miles away.
  • 👥 16 other ZIP codes are made of exactly the same digits (09829, 09892, 28909, 29809, 80299, 80929, …). The farthest-flung twin is 09829 in APO AE, a military post office, 6,548 miles away.
  • 🧭 Farther north than 50% of all ZIP codes, and farther east than 80%.
  • 🎯1,137 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 20899 and you would come out at 39.14°S, 102.78°E — 886 miles from Perth, Australia, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 55m of daylight. Shortest: 9h 25m.
  • 📏 At 0.106 square miles of land, 20899 is bigger than 1% of ZIP codes — about 51 football fields.
🌙 The sky over 20899 today
  • Working out the sun…
🌋 Shake report
  • Checking the USGS…

Source: USGS.

People and housing

Population57This ZIP57
Households57This ZIP57
Housing units93This ZIP93
Median age62.8This ZIP62.8Maryland39.4US 38.9
Median household income$24,417This ZIP$24,417Maryland$103,678US $80,734
Median gross rent$788This ZIP$788Maryland$1,705US $1,413
Bachelor's degree or higher0.0%
Population density537.7 / sq miThis ZIP537.7 / sq mi

Business and tax activity

Business establishments8This ZIP8
Employees198This ZIP198
Annual payroll$12,362,000This ZIP$12,362,000

Land area

Land area0.11 sq miThis ZIP0.11 sq mi
Water area0.00 sq mi

Other place names in 20899

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

ZIP codes near 20899

ZIPCityDistance
20813 Bethesda, MD 0.5 mi
20827 Bethesda, MD 0.5 mi
20848 Rockville, MD 0.5 mi
20859 Potomac, MD 0.5 mi
20875 Germantown, MD 0.5 mi
20884 Gaithersburg, MD 0.5 mi
20897 Suburb Maryland Fac, MD 0.5 mi
20898 Gaithersburg, MD 0.5 mi
20877 Gaithersburg, MD 1.3 mi
20880 Washington Grove, MD 2.2 mi

Find every ZIP code within 10 miles of 20899 →

Questions about this ZIP code

Where is ZIP code 20899?

20899 is in Gaithersburg, Maryland, in Montgomery County, part of the Washington-Arlington-Alexandria, DC-VA-MD-WV metropolitan area. Its published point location is 39.1444, -77.2162.

What county is 20899 in?

20899 lies in Montgomery County.

What area code is 20899?

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

What time zone is 20899 in?

20899 uses America/New_York.

How many people live in 20899?

About 57 people live in ZIP code 20899, in 57 households, at 537.7 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 20899?

$24,417 a year, against $103,678 across Maryland.

What ZIP codes are near 20899?

The closest are 20813 (0.5 mi), 20827 (0.5 mi), 20848 (0.5 mi), 20859 (0.5 mi) and 20875 (0.5 mi).

Is 20899 a PO Box ZIP code?

20899 is a standard ZIP code. A normal ZIP code with street delivery.

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zipcodes.pro. “20899 ZIP Code — Gaithersburg, Maryland (Montgomery County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/20899

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