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/20877

20877

ZIP 20877 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
38,546
Coordinates
39.1406, -77.1921
☼ Live from 20877 — Gaithersburg, MD

Weather right now

Asking the National Weather Service…

NEXRAD radar
Finding the nearest radar…
Local time: —

Where 20877 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 20877
  • 🔢 Type 20877 into a pocket calculator and turn it upside down: LLBOZ — not quite a word, sorry.
  • ➕ As a number, 20,877 = 3 × 6959. Its digits add up to 24, a total 2,425 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 101000110001101
  • 🏠 Its numerical neighbours: 20876 (Germantown, MD, 5 mi away) and 20878 (Gaithersburg, MD, 4 mi away).
  • 🔄 Backwards, 20877 becomes 77802 — and that is a real ZIP code: Bryan, TX, 1,229 miles away.
  • 👥 30 other ZIP codes are made of exactly the same digits (02877, 07728, 07827, 20778, 20787, 27708, …). The farthest-flung twin is 87027 in La Jara, NM, 1,634 miles away.
  • 🧭 Farther north than 50% of all ZIP codes, and farther east than 81%.
  • 🎯1,139 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 20877 and you would come out at 39.14°S, 102.81°E — 885 miles from Perth, Australia, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 55m of daylight. Shortest: 9h 25m.
  • 📏 At 5.6 square miles of land, 20877 is bigger than 20% of ZIP codes — room for about 4.3 Central Parks.
🌙 The sky over 20877 today
  • Working out the sun…
🌋 Shake report
  • Checking the USGS…

Source: USGS.

People and housing

Population38,546This ZIP38,546
Households12,519This ZIP12,519
Housing units13,272This ZIP13,272
Median age36.8This ZIP36.8Maryland39.4US 38.9
Median household income$92,800This ZIP$92,800Maryland$103,678US $80,734
Median home value$474,800This ZIP$474,800Maryland$419,900US $332,700
Median gross rent$1,887This ZIP$1,887Maryland$1,705US $1,413
Bachelor's degree or higher33.4%This ZIP33.4%
Mean commute30.7 minThis ZIP30.7 min
Population density6,841.7 / sq miThis ZIP6,841.7 / sq mi

Business and tax activity

Business establishments1,151This ZIP1,151
Employees16,866This ZIP16,866
Annual payroll$998,358,000This ZIP$998,358,000
Tax returns filed19,900This ZIP19,900
Total adjusted gross income$1,169,468,000This ZIP$1,169,468,000

Land area

Land area5.63 sq miThis ZIP5.63 sq mi
Water area0.03 sq miThis ZIP0.03 sq mi

Other place names in 20877

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

ZIP codes near 20877

ZIPCityDistance
20813 Bethesda, MD 0.9 mi
20827 Bethesda, MD 0.9 mi
20848 Rockville, MD 0.9 mi
20859 Potomac, MD 0.9 mi
20875 Germantown, MD 0.9 mi
20884 Gaithersburg, MD 0.9 mi
20897 Suburb Maryland Fac, MD 0.9 mi
20898 Gaithersburg, MD 0.9 mi
20880 Washington Grove, MD 0.9 mi
20899 Gaithersburg, MD 1.3 mi

Find every ZIP code within 10 miles of 20877 →

Questions about this ZIP code

Where is ZIP code 20877?

20877 is in Gaithersburg, Maryland, in Montgomery County, part of the Washington-Arlington-Alexandria, DC-VA-MD-WV metropolitan area. Its published point location is 39.1406, -77.1921.

What county is 20877 in?

20877 lies in Montgomery County.

What area code is 20877?

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

What time zone is 20877 in?

20877 uses America/New_York.

How many people live in 20877?

About 38,546 people live in ZIP code 20877, in 12,519 households, at 6,841.7 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 20877?

$92,800 a year, against $103,678 across Maryland.

What ZIP codes are near 20877?

The closest are 20813 (0.9 mi), 20827 (0.9 mi), 20848 (0.9 mi), 20859 (0.9 mi) and 20875 (0.9 mi).

Is 20877 a PO Box ZIP code?

20877 is a standard ZIP code. A normal ZIP code with street delivery.

Download or cite

Cite this page

zipcodes.pro. “20877 ZIP Code — Gaithersburg, Maryland (Montgomery County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/20877

Machine-readable version of these facts:

curl https://zipcodes.pro/zip/20877.json

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