20818 ZIP Code, Cabin John, MD
20818 is a ZIP code in Cabin John, Maryland in Montgomery County. It covers 0.9 square miles of land. The closest ZIP codes are 20812, 20817 and 22101. 1,539 people live here in 593 households. At about 1,658 people per square mile it has suburban density, and most homes are owner-occupied (95%). Median household income is $245,982, well above the Maryland median of $103,678; the median age is 52.7, older than most ZIP codes.
Quick facts
- Mailing city: Cabin John, MD
- County: Montgomery County
- Land area: 0.9 sq mi
- Population: 1,539
- Median household income: $245,982
- Carrier routes: 2 (684 homes)
Key figures
| Measure | Value |
|---|---|
| Residents | 1,539 |
| Households | 593 |
| Median household income | $245,982 |
| Income per person | $159,058 |
| Median age | 52.7 |
| Homeowners | 95.3% |
| Median home value | $1,335,100 |
| Median rent | not published |
| Bachelor's degree or higher | 86.4% |
| Average commute (minutes) | 30.1 |
| Households with kids under 18 | 31.9% |
| Moved in the past year | 5.0% |
| Below the poverty line | 1.1% |
| Broadband internet | 100.0% |
| Speak a non-English language at home | 26.2% |
Household income
| % of households | Value |
|---|---|
| <$10K | 0.0% |
| $10–15K | 0.0% |
| $15–25K | 0.0% |
| $25–35K | 5.2% |
| $35–50K | 10.6% |
| $50–75K | 3.0% |
| $75–100K | 2.5% |
| $100–150K | 2.4% |
| $150–200K | 14.3% |
| $200K+ | 61.9% |
Age
| % of all residents | Value |
|---|---|
| <10 | 13.0% |
| 10–19 | 9.8% |
| 20–24 | 3.6% |
| 25–34 | 3.1% |
| 35–44 | 10.6% |
| 45–54 | 15.7% |
| 55–64 | 20.6% |
| 65–74 | 10.1% |
| 75+ | 13.5% |
Tenure
| % of housing units | Value |
|---|---|
| Owned, with mortgage | 67.7% |
| Owned outright | 18.3% |
| Rented | 4.3% |
| Vacant | 9.7% |
Type of building
| % of housing units | Value |
|---|---|
| Detached house | 88.0% |
| Townhome | 12.0% |
| 2–4 units | 0.0% |
| 5–19 units | 0.0% |
| 20+ units | 0.0% |
| Mobile / other | 0.0% |
Businesses in 20818
52 business establishments with 500 employees (ZIP Codes Business Patterns 2023).
- Professional, Scientific, and Technical Services: 15
- Construction: 8
- Health Care and Social Assistance: 6
- Accommodation and Food Services: 6
- Information: 5
- Other Services (except Public Administration): 3
EDDM carrier routes
20818 has 2 USPS carrier routes with 684 residential and 49 business mailboxes. Open the EDDM route map.
Carrier routes in 20818
20818 has 2 USPS carrier routes (2 city (C)) with 684 residential and 49 business mailboxes. Routes range from 237 homes (C001) to 447 homes (C002); the median route has 342 homes. The Census counted 593 households in 20818 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.
| Homes per route | Routes |
|---|---|
| 1–249 | 1 |
| 250–499 | 1 |
| 500–749 | 0 |
| 750–999 | 0 |
| 1,000–1,499 | 0 |
| 1,500+ | 0 |
Best routes in 20818 for…
Most businesses
For B2B offers: office supplies, cleaning, IT, catering and commercial services.
- Route C002 — USPS business mailboxes 45, 447 homes
- Route C001 — USPS business mailboxes 4, 237 homes
Select these 2 routes on the route map
Every carrier route in 20818
| Route | Type | Homes | Businesses | Est. median income | Est. owners | Est. families with kids | Est. moved in past year |
|---|---|---|---|---|---|---|---|
| C001 | City | 237 | 4 | $200,001+ | — | — | — |
| C002 | City | 447 | 45 | $200,001+ | — | — | — |
Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 20818 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
- 20812 — Glen Echo town, MD (1.1 mi)
- 20817 — Bethesda CDP, MD (1.7 mi)
- 22101 — McLean CDP, VA (2.3 mi)
- 20816 — Bethesda CDP, MD (2.5 mi)
- 20894 — Bethesda CDP, MD (3.6 mi)
- 20892 — Bethesda CDP, MD (3.7 mi)
- 20814 — Bethesda CDP, MD (3.9 mi)
- 22102 — McLean CDP, VA (3.9 mi)
Areas that include 20818
- Cabin John, MD ZIP codes — 3 ZIP codes
- Montgomery County ZIP codes — 48 ZIP codes
- Maryland ZIP code data
Where it ranks
- No. 3 of 36: highest median household income in Montgomery County
- No. 1 of 37: highest median home value in Montgomery County
- No. 3 of 37: highest share of owner-occupied homes in Montgomery County
- No. 1 of 37: highest median age in Montgomery County
Mail every home in 20818
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) 20818, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.
Frequently asked questions
- What city is 20818 in?
- 20818 is a Cabin John, MD mailing address. By land area, 100% lies inside Cabin John.
- What county is 20818 in?
- 20818 is in Montgomery County.
- What is the population of 20818?
- About 1,539 people (±366), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 1,832.
- What is the median household income in 20818?
- $245,982 (±$53,171), 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 20818?
- 2 USPS carrier routes with 684 residential and 49 business mailboxes (733 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
- What ZIP codes are near 20818?
- The closest, measured center to center: 20812 (1.1 mi, Glen Echo), 20817 (1.7 mi, Bethesda), 22101 (2.3 mi, McLean), 20816 (2.5 mi, Bethesda), 20894 (3.6 mi, Bethesda) and 20892 (3.7 mi, Bethesda).
This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.