20877 ZIP Code, Gaithersburg, MD
20877 is a ZIP code in Gaithersburg, Maryland in Montgomery County. It covers 5.6 square miles of land. The closest ZIP codes are 20880, 20899 and 20879. 38,546 people live here in 12,519 households. At about 6,842 people per square mile it is built up to city-neighborhood density, and owners and renters are mixed (43% own). Median household income is $92,800, below the Maryland median of $103,678.
Quick facts
- Mailing city: Gaithersburg, MD
- County: Montgomery County
- Land area: 5.6 sq mi
- Population: 38,546
- Median household income: $92,800
- Carrier routes: 26 (13,642 homes)
Key figures
| Measure | Value |
|---|---|
| Residents | 38,546 |
| Households | 12,519 |
| Median household income | $92,800 |
| Income per person | $38,973 |
| Median age | 36.8 |
| Homeowners | 43.1% |
| Median home value | $474,800 |
| Median rent | $1,887 |
| Bachelor's degree or higher | 33.4% |
| Average commute (minutes) | 30.7 |
| Households with kids under 18 | 35.9% |
| Moved in the past year | 15.6% |
| Below the poverty line | 12.0% |
| Broadband internet | 94.2% |
| Speak a non-English language at home | 62.6% |
Household income
| % of households | Value |
|---|---|
| <$10K | 5.8% |
| $10–15K | 2.4% |
| $15–25K | 4.6% |
| $25–35K | 4.5% |
| $35–50K | 10.7% |
| $50–75K | 14.9% |
| $75–100K | 9.5% |
| $100–150K | 19.9% |
| $150–200K | 12.9% |
| $200K+ | 15.0% |
Age
| % of all residents | Value |
|---|---|
| <10 | 14.3% |
| 10–19 | 13.6% |
| 20–24 | 5.6% |
| 25–34 | 13.2% |
| 35–44 | 16.1% |
| 45–54 | 12.2% |
| 55–64 | 10.3% |
| 65–74 | 7.8% |
| 75+ | 6.9% |
Tenure
| % of housing units | Value |
|---|---|
| Owned, with mortgage | 28.6% |
| Owned outright | 12.2% |
| Rented | 53.5% |
| Vacant | 5.7% |
Type of building
| % of housing units | Value |
|---|---|
| Detached house | 23.0% |
| Townhome | 23.5% |
| 2–4 units | 4.0% |
| 5–19 units | 26.0% |
| 20+ units | 23.6% |
| Mobile / other | 0.0% |
Businesses in 20877
1,151 business establishments with 16,866 employees (ZIP Codes Business Patterns 2023).
- Health Care and Social Assistance: 177
- Retail Trade: 158
- Professional, Scientific, and Technical Services: 152
- Construction: 122
- Other Services (except Public Administration): 105
- Accommodation and Food Services: 93
- Administrative and Support and Waste Management and Remediation Services: 73
- Wholesale Trade: 65
EDDM carrier routes
20877 has 26 USPS carrier routes with 13,642 residential and 1,508 business mailboxes. Open the EDDM route map.
Carrier routes in 20877
20877 has 26 USPS carrier routes (26 city (C)) with 13,642 residential and 1,508 business mailboxes. Routes range from 56 homes (C058) to 921 homes (C011); the median route has 587 homes. The Census counted 12,519 households in 20877 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.
| Homes per route | Routes |
|---|---|
| 1–249 | 3 |
| 250–499 | 6 |
| 500–749 | 14 |
| 750–999 | 3 |
| 1,000–1,499 | 0 |
| 1,500+ | 0 |
Best routes in 20877 for…
Most businesses
For B2B offers: office supplies, cleaning, IT, catering and commercial services.
- Route C004 — USPS business mailboxes 279, 149 homes
- Route C014 — USPS business mailboxes 197, 190 homes
- Route C010 — USPS business mailboxes 174, 285 homes
- Route C026 — USPS business mailboxes 142, 607 homes
- Route C017 — USPS business mailboxes 119, 575 homes
Select these 5 routes on the route map
Every carrier route in 20877
| Route | Type | Homes | Businesses | Est. median income | Est. owners | Est. families with kids | Est. moved in past year |
|---|---|---|---|---|---|---|---|
| C001 | City | 305 | 94 | $104,021 | — | — | — |
| C003 | City | 697 | 19 | $120,939 | — | — | — |
| C004 | City | 149 | 279 | $79,425 | — | — | — |
| C005 | City | 615 | 60 | $65,251 | — | — | — |
| C006 | City | 340 | 19 | $79,425 | — | — | — |
| C009 | City | 666 | 21 | $65,251 | — | — | — |
| C010 | City | 285 | 174 | $66,309 | — | — | — |
| C011 | City | 921 | 5 | $103,016 | — | — | — |
| C012 | City | 309 | 112 | $117,454 | — | — | — |
| C013 | City | 646 | 2 | $84,735 | — | — | — |
| C014 | City | 190 | 197 | — | — | — | — |
| C015 | City | 378 | 103 | — | — | — | — |
| C016 | City | 547 | 1 | $134,389 | — | — | — |
| C017 | City | 575 | 119 | $66,309 | — | — | — |
| C019 | City | 631 | 62 | $52,940 | — | — | — |
| C020 | City | 517 | 1 | $193,013 | — | — | — |
| C021 | City | 779 | 70 | $66,309 | — | — | — |
| C022 | City | 609 | 14 | $122,854 | — | — | — |
| C023 | City | 697 | 3 | $134,389 | — | — | — |
| C024 | City | 599 | 2 | $109,427 | — | — | — |
| C026 | City | 607 | 142 | $52,940 | — | — | — |
| C027 | City | 467 | 0 | $77,847 | — | — | — |
| C030 | City | 806 | 2 | $52,940 | — | — | — |
| C031 | City | 561 | 2 | $165,897 | — | — | — |
| C057 | City | 690 | 4 | $103,016 | — | — | — |
| C058 | City | 56 | 1 | $77,847 | — | — | — |
Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 20877 on the EDDM route map.
How route demographics are estimated
Mailbox counts come from USPS; demographics are estimates
The number of homes and businesses on each carrier route is the current USPS EDDM count. The Census Bureau does not publish figures for carrier routes, so income, homeownership, ages, families, movers and housing age on a route are EDDM2GO estimates built from Census block groups (neighborhood areas of roughly 600 to 3,000 people).
How a route gets its figures: the block-group length-share method
We trace each route's streets every 25 meters and record which block group each stretch falls in. The route's homes are spread along its streets in proportion to length, so a route with 60% of its street length in one block group is assumed to have 60% of its homes there. Each block group then contributes its Census counts in proportion to the share of its housing units that sit on the route (capped at the whole block group). Medians are recalculated from the combined income, home-value and age brackets, the way the Census Bureau computes them, not averaged.
Margins of error
Census survey figures carry a margin of error at 90% confidence; we carry it through the calculation and show it as ±. Our margins treat the route-to-block-group split as exact, so the real uncertainty is larger. Routes with fewer than 100 estimated households, large margins, or streets we could not place are flagged.
Different years
USPS mailbox counts are current. Census figures are 5-year averages for 2020–2024, so a new subdivision may have more homes on the route today than the Census counted. Use the route figures to compare routes with each other, not as an exact head count.
Why some routes show identical figures
Two routes that run through the same block group get the same percentages and medians, because the Census publishes one set of figures for the whole block group. Their mailbox counts still differ, and those are exact.
Route and mailbox counts: USPS EDDM route data. Route demographics: EDDM2GO estimates from U.S. Census Bureau American Community Survey 5-year block-group data (2020–2024) and 2024 cartographic block-group boundaries. This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.
Nearby ZIP codes
- 20880 — Washington Grove town, MD (0.9 mi)
- 20899 — Gaithersburg city, MD (1.3 mi)
- 20879 — Flower Hill CDP, MD (2.4 mi)
- 20855 — Redland CDP, MD (3.2 mi)
- 20886 — Montgomery Village CDP, MD (3.4 mi)
- 20850 — Rockville city, MD (3.6 mi)
- 20878 — Gaithersburg city, MD (3.7 mi)
- 20876 — Germantown CDP, MD (5.1 mi)
Areas that include 20877
- Gaithersburg, MD ZIP codes — 5 ZIP codes
- Redland, MD ZIP codes — 2 ZIP codes
- Montgomery County ZIP codes — 48 ZIP codes
- Maryland ZIP code data
Where it ranks
- No. 5 of 37: highest share of residents who moved in during the past year in Montgomery County
- No. 5 of 37: lowest median age in Montgomery County
Mail every home in 20877
Route counts on this page price as Full Service 6.5 × 9 postcards: we print, bundle by carrier route and hand the mailing to USPS. Prefer to take it to the Post Office yourself? Print only costs less and you pay postage at drop-off.
EDDM guides
ZIP code statistics describe the Census ZIP Code Tabulation Area (ZCTA) 20877, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.
Frequently asked questions
- What city is 20877 in?
- 20877 is a Gaithersburg, MD mailing address. By land area, 66% lies inside Gaithersburg, 13% lies inside Redland, 3% lies inside Flower Hill and 1% lies inside Montgomery Village; the rest is outside any Census-defined city or community.
- What county is 20877 in?
- 20877 is in Montgomery County.
- What is the population of 20877?
- About 38,546 people (±1,841), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 37,577.
- What is the median household income in 20877?
- $92,800 (±$12,435), compared with $103,678 for Maryland as a whole. Half the households in the ZIP code earn more and half earn less.
- How many carrier routes and mailboxes are in 20877?
- 26 USPS carrier routes with 13,642 residential and 1,508 business mailboxes (15,151 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
- What ZIP codes are near 20877?
- The closest, measured center to center: 20880 (0.9 mi, Washington Grove), 20899 (1.3 mi, Gaithersburg), 20879 (2.4 mi, Flower Hill), 20855 (3.2 mi, Redland), 20886 (3.4 mi, Montgomery Village) and 20850 (3.6 mi, Rockville).
This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.