94027 ZIP Code, Atherton, CA
94027 is a ZIP code in Atherton, California in San Mateo County. It covers 5.0 square miles of land. The closest ZIP codes are 94025, 94061 and 94063. 7,002 people live here in 2,236 households. At about 1,393 people per square mile it has suburban density, and most homes are owner-occupied (88%). Median household income is $250,000+, well above the California median of $99,122; the median age is 49.1, older than most ZIP codes.
Quick facts
- Mailing city: Atherton, CA
- County: San Mateo County
- Land area: 5.0 sq mi
- Population: 7,002
- Median household income: $250,000+
- Carrier routes: 8 (2,478 homes)
Key figures
| Measure | Value |
|---|---|
| Residents | 7,002 |
| Households | 2,236 |
| Median household income | $250,000+ |
| Income per person | $188,761 |
| Median age | 49.1 |
| Homeowners | 87.6% |
| Median home value | $2,000,000+ |
| Median rent | $3,501 |
| Bachelor's degree or higher | 83.2% |
| Average commute (minutes) | 23.1 |
| Households with kids under 18 | 29.7% |
| Moved in the past year | 14.7% |
| Below the poverty line | 5.3% |
| Broadband internet | 97.6% |
| Speak a non-English language at home | 28.9% |
Household income
| % of households | Value |
|---|---|
| <$10K | 3.0% |
| $10–15K | 1.2% |
| $15–25K | 3.1% |
| $25–35K | 0.3% |
| $35–50K | 2.1% |
| $50–75K | 1.8% |
| $75–100K | 4.7% |
| $100–150K | 11.5% |
| $150–200K | 6.8% |
| $200K+ | 65.6% |
Age
| % of all residents | Value |
|---|---|
| <10 | 5.0% |
| 10–19 | 19.6% |
| 20–24 | 9.3% |
| 25–34 | 7.0% |
| 35–44 | 4.4% |
| 45–54 | 14.7% |
| 55–64 | 14.2% |
| 65–74 | 11.8% |
| 75+ | 13.9% |
Tenure
| % of housing units | Value |
|---|---|
| Owned, with mortgage | 36.5% |
| Owned outright | 36.9% |
| Rented | 10.3% |
| Vacant | 16.3% |
Type of building
| % of housing units | Value |
|---|---|
| Detached house | 97.3% |
| Townhome | 2.0% |
| 2–4 units | 0.7% |
| 5–19 units | 0.0% |
| 20+ units | 0.0% |
| Mobile / other | 0.0% |
Businesses in 94027
180 business establishments with 1,883 employees (ZIP Codes Business Patterns 2023).
- Professional, Scientific, and Technical Services: 42
- Real Estate and Rental and Leasing: 27
- Finance and Insurance: 23
- Health Care and Social Assistance: 20
- Other Services (except Public Administration): 15
- Information: 8
- Educational Services: 7
- Accommodation and Food Services: 7
EDDM carrier routes
94027 has 8 USPS carrier routes with 2,478 residential and 53 business mailboxes. Open the EDDM route map.
Carrier routes in 94027
94027 has 8 USPS carrier routes (8 city (C)) with 2,478 residential and 53 business mailboxes. Routes range from 249 homes (C075) to 383 homes (C065); the median route has 305 homes. The Census counted 2,236 households in 94027 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.
| Homes per route | Routes |
|---|---|
| 1–249 | 1 |
| 250–499 | 7 |
| 500–749 | 0 |
| 750–999 | 0 |
| 1,000–1,499 | 0 |
| 1,500+ | 0 |
Best routes in 94027 for…
Most businesses
For B2B offers: office supplies, cleaning, IT, catering and commercial services.
- Route C001 — USPS business mailboxes 25, 253 homes
- Route C013 — USPS business mailboxes 11, 339 homes
- Route C047 — USPS business mailboxes 10, 350 homes
- Route C065 — USPS business mailboxes 4, 383 homes
- Route C075 — USPS business mailboxes 2, 249 homes
Select these 5 routes on the route map
Every carrier route in 94027
| Route | Type | Homes | Businesses | Est. median income | Est. owners | Est. families with kids | Est. moved in past year |
|---|---|---|---|---|---|---|---|
| C001 | City | 253 | 25 | $200,001+ | — | — | — |
| C013 | City | 339 | 11 | $200,001+ | — | — | — |
| C019 | City | 294 | 0 | $200,001+ | — | — | — |
| C037 | City | 310 | 0 | $200,001+ | — | — | — |
| C047 | City | 350 | 10 | $200,001+ | — | — | — |
| C061 | City | 300 | 1 | $200,001+ | — | — | — |
| C065 | City | 383 | 4 | $200,001+ | — | — | — |
| C075 | City | 249 | 2 | $200,001+ | — | — | — |
Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 94027 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
- 94025 — Menlo Park city, CA (1.1 mi)
- 94061 — Redwood City city, CA (2 mi)
- 94063 — Redwood City city, CA (2.5 mi)
- 94301 — Palo Alto city, CA (2.9 mi)
- 94305 — Stanford CDP, CA (3.2 mi)
- 94304 — Palo Alto city, CA (4.5 mi)
- 94303 — Palo Alto city, CA (4.7 mi)
- 94070 — San Carlos city, CA (4.8 mi)
Areas that include 94027
- Atherton, CA ZIP codes — 1 ZIP code
- San Mateo County ZIP codes — 31 ZIP codes
- California ZIP code data
Where it ranks
- No. 1 of 28: highest median household income in San Mateo County
- No. 7 of 28: highest median home value in San Mateo County
- No. 2 of 28: highest share of owner-occupied homes in San Mateo County
- No. 5 of 28: highest share of residents who moved in during the past year in San Mateo County
- No. 4 of 28: highest median age in San Mateo County
Mail every home in 94027
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) 94027, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.
Frequently asked questions
- What city is 94027 in?
- 94027 is a Atherton, CA mailing address. By land area, 100% lies inside Atherton.
- What county is 94027 in?
- 94027 is in San Mateo County.
- What is the population of 94027?
- About 7,002 people (±25), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 7,270.
- What is the median household income in 94027?
- $250,000+, compared with $99,122 for California as a whole. Half the households in the ZIP code earn more and half earn less.
- How many carrier routes and mailboxes are in 94027?
- 8 USPS carrier routes with 2,478 residential and 53 business mailboxes (2,531 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
- What ZIP codes are near 94027?
- The closest, measured center to center: 94025 (1.1 mi, Menlo Park), 94061 (2 mi, Redwood City), 94063 (2.5 mi, Redwood City), 94301 (2.9 mi, Palo Alto), 94305 (3.2 mi, Stanford) and 94304 (4.5 mi, Palo Alto).
This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.