Contra Costa County, California Demographics
Population trends, housing costs, income, commuting, and health, all on one page.
Contra Costa County, CA Population Density Map and Area Scores
Area Score
Health, income and education, each graded from F to A+. Explore interactive maps for deeper analysis.
-
A
Health Above averageHealthier than 88% of counties in California
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B
Income Around averageAmong the top 5 wealthiest counties in California
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A
Education Above averageBetter educated than 91% of counties in California
Source: Map AI Methodology
Population: density and quick facts
| Metric | Contra Costa County | California Avg | U.S. Average |
|---|---|---|---|
| Population | 1,163,035 | 39,245,658 | 337,468,954 |
| Population density (per sq mi) | 1447.6 | 239.4 | 86.4 |
| Population growth (%/yr) | 0.55% | 0.19% | 0.59% |
| Median age | 40.9 | 35.5 | 37.3 |
| Households | 413,694 | 13,531,619 | 130,235,071 |
Population in Contra Costa County grew by 14.0% from 2009 to 2024, reaching 1,163,035 in 2024.
Population Growth 2009–2024
Race & Ethnicity
Age & Sex
The largest generation in Contra Costa County is Millennials, aged 29–44, at 22.4% of residents. That is 1.2 points below California as a whole.
- Gen Z 13–28 231,376 19.9% -1.8 pts
- Millennials 29–44 260,878 22.4% -1.2 pts
- Gen X 45–60 254,222 21.9% +2.0 pts
- Boomers 61–79 192,635 16.6% +1.3 pts
Residents by birth cohort, from the 2025 age distribution. The right-hand figure is how far each cohort's share sits above or below California, in percentage points. Children younger than Gen Z and the generations before the Boomers are counted in the population but not shown here, so these shares do not add up to 100%.
Male and female share
Women are 50.7% of the people living in Contra Costa County and men 49.3%.
- Women 50.7% California 49.9%
- Men 49.3% California 50.1%
How many residents match a customer profile?
Residents matching this profile
100% of everyone living in Contra Costa County
Pick an age range and a women/men split and the figure above answers with how many residents that profile reaches.
Economy
Contra Costa County has a the economy index of B, which means it is quite prosperous.
| Metric | Contra Costa County | California Avg | U.S. Average |
|---|---|---|---|
| Median household income | $127,405 | $99,161 | $80,455 |
| Income growth (%/yr) | 5.39% | 5.57% | 4.80% |
| Unemployment rate | 6.5% | 6.6% | 5.2% |
The median household income in Contra Costa County is about 28% higher than in California.
Housing
| Metric | Contra Costa County | California Avg | U.S. Average |
|---|---|---|---|
| Median home price | $663,272 | $650,794 | $248,835 |
| Median rent | $2,374 | $2,036 | $1,407 |
| Homeownership rate | 68.0% | 55.9% | 65.2% |
The median home price in Contra Costa County is about 23.3 years' worth of rent — buying at the median price costs roughly as much as paying the median rent of $2,374 per month for that long.
Commute Time & Mobility
Commuters in Contra Costa County spend about 62 minutes on the road round trip each working day. Over a typical 250-day work year, that adds up to roughly 258 hours, about 10.8 full days, spent commuting.
| Metric | Contra Costa County | California Avg | U.S. Average |
|---|---|---|---|
| One-way commute (min) | 31.0 | 23.5 | 22.4 |
| Round-trip commute (min) | 62.0 | 47.0 | 44.8 |
| Yearly time spent (hours) | 258 | 196 | 187 |
| Estimated yearly cost | $8,007 | $6,065 | $5,790 |
| Work from home | 21.3% | 17.2% | 15.0% |
| Highway traffic (vehicles/day) | 23,932 | 16,509 | 8,813 |
| Local road traffic (vehicles/day) | 3,453 | 2,449 | 1,355 |
Fastest commutes among counties in
California:
Inyo County (11.1 min), Mono County (12.0 min), Del Norte County (12.1 min).
Slowest:
Alpine County (31.3 min), San Benito County (31.2 min), Contra Costa County (31.0 min).
The average commute time in Contra Costa County is 31 minutes, longer than the 23 minutes in California.
Estimated yearly cost applies a single national wage rule of thumb (U.S. Bureau of Labor Statistics average hourly earnings), not a measurement of wages in this area. Traffic volume figures come from proprietary Ticon and TrafficZoom data.
Education & Households
Contra Costa County has a education index of A, which means it is very educated.
| Metric | Contra Costa County | California Avg | U.S. Average |
|---|---|---|---|
| Bachelor's degree or higher | 41.2% | 33.0% | 31.6% |
| Average household size | 2.78 | 2.84 | 2.53 |
Highest education index among counties in
California:
Marin County (0.5), San Francisco County (0.4), Santa Clara County (0.4).
Lowest:
Colusa County (0.2), Merced County (0.2), Glenn County (0.2).
Health
Contra Costa County has a health index of A, which means it is very healthy.
| Metric | Contra Costa County | California Avg | U.S. Average |
|---|---|---|---|
| Life expectancy (years) | 80.8 | 79.6 | 78.3 |
| Self-rated poor health | 12.9% | 16.4% | 16.3% |
| Smokers | 10.6% | 13.9% | 19.0% |
Highest health index among counties in
California:
San Francisco County (0.8), San Mateo County (0.8), Santa Clara County (0.8).
Lowest:
Lake County (0.8), Imperial County (0.8), Tulare County (0.8).
Contra Costa County, CA Compared With Nearby Counties
Contra Costa County, CA is the 2nd largest of the 6 counties compared here, 1,163,035 residents against a local median of 733,246. Contra Costa County, CA's commute, at 31.0 min, runs 34% above the 23.2 min typical of the counties around it. That is the weaker end of the local range on this measure.
Median home price tells the same story from another angle: $663,272 against a local median of $833,751, 20% below it. The counties themselves spread 8.0 min on commute, so Contra Costa County, CA sits at one end of an already wide local range rather than apart from it. Contra Costa County, CA has the 6th lowest commute of the 6 areas compared here.
| Area | Population | Median household income | Median home price | Commute |
|---|---|---|---|---|
| Contra Costa County, CA | 1,163,035 | $127,405 #3/6 | $663,272 #4/6 | 31.0 min #6/6 |
| Alameda County, CA | 1,648,382 | $129,593 | $833,751 | 28.3 min |
| Solano County, CA | 451,581 | $100,378 | $483,427 | 23.7 min |
| San Mateo County, CA | 733,246 | $159,405 | $1,744,985 | 23.2 min |
| San Joaquin County, CA | 797,313 | $93,025 | $526,211 | 23.2 min |
| Napa County, CA | 134,769 | $112,778 | $902,338 | 20.3 min |
Frequently Asked Questions
Common questions about Contra Costa County, California.
How many people live in Contra Costa County, California?
About 1,163,035 people live in Contra Costa County, California, in 413,694 households of 2.8 people on average. The median age is 40.9, so residents are older than the U.S. median of 37.3 by about 4 years.
How densely populated is Contra Costa County, California?
Averaged over its land area, Contra Costa County, California has 1,448 people per square mile, a density typical of urban and suburban areas. That is about 17 times the U.S. average of 86.
How affordable is housing in Contra Costa County, California?
The median home costs 5.2 times the median household income ($663,272 against $127,405), compared with 3.1 times nationally. A ratio of about 3 is traditionally considered affordable. Median rent of $2,374 a month takes about 22% of the median household's income, below the 30% level at which HUD considers renters cost-burdened.
What share of adults in Contra Costa County, California have a college degree?
41.2% of adults in Contra Costa County, California hold a bachelor's degree or higher (about 1 in 2), well above the U.S. share of 31.6%.
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