| City: | Diablo, California |
| County: | Contra Costa County |
| Timezone: | Pacific (GMT -08:00) |
| Local Time: | 9:52:23 AM |
| Population: | 1,054 [See All] |
| Area Code: | 925 |
| Classification: | PO Box |
| Coordinates: | 37.8414, -121.9628 |
| Land Area: | 1.154 sq mi |
| Quick Link: |
Diablo is an exclusive gated community in Contra Costa County, California, with a population of 1,054 residents across 381 households. The entire community consists of just one street (El Nido) with 47 delivery points, all located within 1.07 square miles. This isn't a typical small town. It's one of California's most exclusive residential enclaves.
The Diablo post office maintains 485 PO Boxes for 381 households, resulting in a 1.27 adoption rate. This is a PO Box Only Zone. There's no carrier delivery to homes despite the community's urban character. Every resident must collect mail at the post office, which is the only delivery option across the ZIP's territory.
Demographics point to extraordinary affluence. The median home value is $2 million, and per capita income reaches $103,701. Among adults, 85% hold bachelor's degrees or higher. The median age of 49.5 years and owner-occupancy rate of 93% (355 of 381 households) indicate an established, wealthy community. Only 26 housing units are rentals.
Diablo's street addressing system uses unit numbers along El Nido, accommodating the community's single-street layout. With 38.5% of workers working from home (17 of 44 workers), the community supports remote professionals and retirees. The combination of high home values, exceptional education levels, and work-from-home flexibility shapes this exclusive enclave.
Standard Format:
Recipient Name
PO Box [Number]
Diablo, CA 94528All mail must be addressed to PO Boxes. Street delivery is not available in this ZIP code.
The entire community consists of one street (El Nido) with unit-numbered addresses.
ZIP Code 94528 has 1,054 residents and 381 households (average 2.77 persons per household). The median age is 49.5 years, significantly older than the state (37.5) and significantly older than the nation (38.8). The gender split is 51.0% male and 49.0% female, which is slightly higher than the national male share (49.1%), making this a male-majority area. Largest groups are White (84.3%, much higher than the state average of 41.2% and well above the national average of 61.6%) and Hispanic or Latino (6.0%); Hispanic or Latino residents make up 6.0%, which is much lower than the state average (39.4%).
Explore More:Population Over TimeBy Age & GenderBy RaceBy GenderNativity & Citizenship
| 2020 Population: | 1,054Source: Census DHC |
| 2024 ACS Population Estimate: | 1,049Source: Census ACS |
| 2026 ZC Population Estimate: | 0Source: ZIP-Codes.com |
| Population Density: | 913.3 people per sq mile |
| Average Income: | $207,500Source: Census ACS |
| Households: | 381Source: Census DHC |
| Average House Value: | $2,000,001Source: Census ACS |
| Persons Per Household: | 2.77Source: Census DHC |
| Average Family Size: | 2.45Source: Census ACS |
| Group | 2010 | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Census ACS Population Estimate | -- | 1,043 | 1,175 | 1,124 | 915 | 767 | 749 | 552 | 307 | 384 | 804 | 655 | 726 | 1,000 | 1,049 |
| Decennial Census | 964 | -- | -- | -- | -- | -- | -- | -- | -- | -- | 1,054 | -- | -- | -- | -- |
Median Age: 49.5
Male Median Age: 49.1
Female Median Age: 50
| Group | < 5 | 5-9 | 10-14 | 15-19 | 20-24 | 25-29 | 30-34 | 35-39 | 40-44 | 45-49 | 50-54 | 55-59 | 60-64 | 65-69 | 70-74 | 75-79 | 80-84 | 85+ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Male | 18 | 36 | 25 | 59 | 32 | 16 | 11 | 27 | 26 | 35 | 45 | 29 | 57 | 53 | 39 | 2 | 4 | 24 |
| Female | 23 | 18 | 45 | 34 | 11 | 23 | 13 | 31 | 23 | 37 | 54 | 36 | 52 | 38 | 32 | 13 | 23 | 10 |
| Total | 41 | 54 | 70 | 93 | 43 | 39 | 24 | 58 | 49 | 72 | 99 | 65 | 109 | 91 | 71 | 15 | 27 | 34 |
| White: | 889 | 86.48% |
| Black: | 5 | 0.49% |
| Hispanic:* | 63 | 6.13% |
| Asian: | 61 | 5.93% |
| American Indian: | 5 | 0.49% |
| Hawaiian: | 0 | 0% |
| Other: | 5 | 0.49% |
| Total: | 1,028 | 100% |
| Gender | Count | % | Median Age |
|---|---|---|---|
| Males: | 538 | 51.04% | 49.1 years |
| Females: | 516 | 48.96% | 50.0 years |
| Total: | 1,054 | 100% | 49.5 years |
| Native, born in the United States: | 898 | 85.61% |
| Native, born in PR, Island Areas, or abroad: | 0 | 0.00% |
| Foreign born, naturalized U.S. citizen: | 151 | 14.39% |
| Foreign born, not a U.S. citizen: | 0 | 14.39% |
| Total Population: | 1,049 | 100% |
| Total Native Population: | 898 | 85.61% |
| Total Foreign-born Population: | 151 | 14.39% |
In 2024, the Median household income is $207,500, which is much higher than the national median ($80,734), is up $53,640 (34.9%) since 2011 and above its 2019 pre-pandemic level by $64,487. Family households earn a median of $248,400 versus $0 for nonfamily households (a difference of $248,400). By gender, male median income is $0 and female is $170,100, which is far above the national female median ($55,274), with a current gap of $170,100 that has narrowed from 2011 to 2024. The labor-force participation rate is 52.1%, which is far less than the national rate (63.5%). The unemployment rate is 7.1%, which is considerably above the national rate (5.2%). The largest occupation group is Management (84.3%).
Explore More:Income Over TimeHousehold IncomeEmployment StatusBy Occupation
| Income Type | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Median Household Income | $153,860 | $219,688 | $223,893 | $162,328 | $0 | $0 | $0 | $140,496 | $143,013 | $250,001 | $0 | $250,001 | $0 | $207,500 |
| Median Family Income | $250,001 | $250,001 | $250,001 | $250,001 | $227,347 | $227,940 | $138,603 | $0 | $0 | $0 | $0 | $250,001 | $0 | $248,400 |
| Median NonFamily Income | $152,941 | $98,750 | $44,291 | $46,739 | $46,317 | $46,996 | $46,938 | $0 | $0 | $0 | $0 | $0 | $0 | $0 |
| Median Male Income | $250,001 | $250,001 | $250,001 | $156,738 | $156,348 | $210,066 | $0 | $0 | $0 | $0 | $0 | $250,001 | $250,001 | $0 |
| Median Female Income | $250,001 | $250,001 | $178,542 | $181,250 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $170,100 |
| Employed: | 408 | 48.40% |
| Unemployed: | 31 | 3.68% |
| Not In Labor Force: | 404 | 47.92% |
| Total: | 843 | 100% |
| Management, business, science, and arts: | 344 | 84.31% |
| Service: | 0 | 0.00% |
| Sales and Office: | 64 | 15.69% |
| Natural resources, construction, and maintenance: | 0 | 0.00% |
| Production, transportation, and material moving: | 0 | 0.00% |
| Total Civilian Employed Population: | 408 | 100% |
In 2024, the median home value is $2,000,001, which is considerably higher than the national median ($332,700), is up $1,000,000 (100.00%) since 2011 and above its 2019 pre-pandemic level by $0. The median gross rent is $0, which is well under the national median ($1,413), and above its 2019 pre-pandemic level by $0. Of occupied housing, owners make up 100.00% (45.52% with a mortgage, 54.48% free-and-clear) and renters 0.00% - making this ZIP Code under national rental averages. The vacancy rate is 8.42%, which is far lower than the national rate (10.12%).
Explore More:Compare Home ValueHome Value Over TimeRent & Over TimeHousing Occupancy
| Group | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Median Home Value | $1,000,001 | $1,000,001 | $1,000,001 | $1,000,001 | $1,064,600 | $1,277,800 | $1,612,000 | $2,000,001 | $2,000,001 | $2,000,001 | $2,000,001 | $2,000,001 | $2,000,001 | $2,000,001 |
| Less than $500: | 0 | 0% |
| $500 to $999: | 0 | 0% |
| $1,000 to $1,499: | 0 | 0% |
| $1,500 to $1,999: | 0 | 0% |
| $2,000 to $2,499: | 0 | 0% |
| $2,500 to $2,999: | 0 | 0% |
| $3,000 or more: | 0 | 0% |
| No Rent: | 0 | 0% |
| Total: | 0 | 100% |
| Group | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Median Rent | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 |
| Owner Occupied (with mortgage): | 193 | 45.52% |
| Owner Occupied (free and clear, no mortgage): | 231 | 54.48% |
| Renter Occupied: | 0 | 0.00% |
| Total Occupied Housing Units: | 424 | 100% |
| Occupied Housing Units: | 424 | 91.58% |
| Vacant Housing Units (not graphed): | 39 | 8.42% |
| Total Housing Units: | 463 | 100% |
| Single-Family Units: | 463 | 100.00% |
| Multi-Family Units: | 0 | 0.00% |
| Other Units: | 0 | 0.00% |
| Total Housing Units: | 463 | 100% |
In 2024, 79.80% of adults (25+) have a bachelor's degree or higher, which is far higher than the national rate (35.70%). High school or higher is 100.00%, which is far higher than the national rate (89.60%). The uninsured rate is 3.90%, which is comparable to the national rate (8.40%). Private coverage is 85.90%, which is well above the national rate (67.10%). The share of people in poverty is 7.70%, which is comparable to the national rate (8.80%), up 9.90 percentage points since 2011 and above its 2019 pre-pandemic level by 9.90 percentage points. This signals a sharp increase in hardship - a shrinking consumer base, heavy pressure on public services, and job-market contraction risks. Among residents ages 3+, the largest enrollment group is high school (26.92%). College enrollment is 9.94%, which is far lower than the national rate (26.70%), indicating the community may be more oriented toward vocational/trade or direct-to-workforce opportunities.
Explore More:Educational AttainmentHealth InsurancePoverty Over TimeSchool Enrollment
| Less than 9th grade: | 0 | 0.00% |
| 9th to 12th grade, no diploma: | 0 | 0.00% |
| High school graduate (includes equivalency): | 0 | 0.00% |
| Some college, no degree: | 102 | 14.01% |
| Associate's degree: | 45 | 6.18% |
| Bachelor's degree: | 151 | 20.74% |
| Graduate or professional degree: | 430 | 59.07% |
| Total: | 728 | 100% |
| High school or higher: | 728 | 100.00% |
| Bachelor's degree or higher: | 581 | 79.81% |
| Private Insurance: | 901 | 76.42% |
| Public Insurance: | 237 | 20.10% |
| No Insurance: | 41 | 3.48% |
| Total: | 1,179 | 100% |
| Has Health Insurance: | 1,138 | 96.52% |
| Group | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| % of People in Poverty | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 15.7% | 9.9% | 7.7% |
Note: Counts of Families & People in poverty are not published at the ZIP Code level due to small sample sizes. Percentages shown are survey estimates from the American Community Survey (ACS). They may differ from official poverty statistics. The U.S. Census Bureau defines poverty status by comparing a family's or individual's total income with federal poverty thresholds that vary by family size and composition.
| Nursery School, Preschool: | 67 | 21.47% |
| Kindergarten: | 70 | 22.44% |
| Elementary school (grades 1-8): | 60 | 19.23% |
| High school (grades 9-12): | 84 | 26.92% |
| College or graduate school: | 31 | 9.94% |
| Total: | 312 | 100% |
| Early Childhood: | 137 | 43.91% |
| K-12 (Primary & Secondary School): | 214 | 68.59% |
ZIP Code 94528 supports both business and residential activity. According to the Business Census (2024), there are 22 business establishments, employing about 170 people with an annual payroll of $13,196,000.
| # Residential Mailboxes: | 0Source: USPS |
| # Business Mailboxes: | 0Source: USPS |
| Total Delivery Receptacles: | 532Source: USPS |
| Single Family Delivery Units: | 0Source: USPS |
| Multi Family Delivery Units: | 0Source: USPS |
| # of Businesses: | 22Source: CBP |
| 1st Quarter Payroll: | $3,126,000Source: CBP |
| Annual Payroll: | $13,196,000Source: CBP |
| # of Employees: | 170Source: CBP |
ZIP Code 94528 is located in Contra Costa County, California, within the San Francisco-Oakland-Fremont, CA Metropolitan Statistical Area (CBSA 41860) and California's 10th Congressional District. This Metro area has a population of 4,335,391 people, about 0.02% of whom live in ZIP Code 94528, and is subdivided into the Oakland-Fremont-Berkeley, CA division. It covers 1.154 sq mi of land and a water area of 0 sq mi.
| CBSA Name: | San Francisco-Oakland-Fremont, CASource: Census |
| CBSA Number: | 41860Source: Census |
| CBSA Type: | MetroSource: Census |
| CBSA Division: | Oakland-Fremont-Berkeley, CA (CBSA Div 36084)Source: Census |
| CBSA Population: | 4,335,391Source: Census |
| MSA: | San Francisco-Oakland-San Jose, CA CMSASource: Census |
| Land Area: | 1.154 sq miSource: Census |
| Water Area: | --Source: Census |
| Congressional District: | 10Source: USPS |
| Congressional Land Area: | 1818.79 sq miSource: Census |
| PMSA: | Oakland, CA PMSASource: Census |
| Intro Date: | < 2004-10Source: ZIP-Codes.com |
| Place FIPS Code: | 0619150Source: Census |
| Place Name: | Diablo CDP; CaliforniaSource: Census |
We could not locate which school district 94528 belongs to, but we will update this once new district data is released. There are no public schools nor private schools with a mailing address in this ZIP Code. Listing Nearby schools instead. It also has 6 colleges, universities or post secondary education institutions nearby which would be a short commute to.
Our sources include trusted federal and licensed data from the United States Postal Service, U.S. Census Bureau, U.S. Geological Survey, Centers for Medicare & Medicaid Services, and the National Center for Education Statistics, along with proprietary datasets created by ZIP-Codes.com. Data last updated on February 1, 2026.