Contra Costa County is just east of San Francisco, and is one of the most populous counties in the state. The county offers several high-quality amenities, such as theaters and sports venues, along with great outdoor recreation choices at nearby Mount Diablo State Park, or along miles of trails that crisscross the area’s picturesque hills. There are several large metropolitan areas along the coast and in the mountains of California.
As of 2026 the population of Contra Costa County is 1,181,646. The population is expected to grow to 1,192,452 by 2031 - a growth rate of 0.18%.
The median age of Contra Costa County residents is 41.
The diversity index of Contra Costa County is 85.1, meaning that there is a 85% chance that any two people selected out of 100 residents will be of different race or ethnicity from one another.
The average household income in Contra Costa County is $191,617 and projected to be $213,494 in 2031. Per capita income is $67,931, projected to be $76,179 in 2031. 11.48% of households – 135,639 – have an income of $200,000 or higher. Average net worth is $2,597,456 and the average disposable income is $132,211.
There are 435,338 housing units in Contra Costa County; 276,565 are owner-occupied, 141,388 are rented, and 17,385 are vacant. The average home value is $1,099,428, with 29,553 homes built in 2010 or later, and 18,236 built in 1939 or earlier.
There are 37,718 businesses in Contra Costa County, employing 353,099 workers and pulling from a labor force of 551,854 age 16 and above. 184,822 workers commute into Contra Costa County from outside the county or state. Key industries for the area include:
364,931 residents both live and work in/around Contra Costa County. The average travel time is 35.3 minutes. 2.25% people have a commute of less than 5 minutes while 7.91% commute 90 minutes or more each way. Of commuters, 329,327 drive alone, 55,380 carpool, and 29,697 take public transportation. 19,001 use other modes of transport such as motorcycle, bicycle, walking, etc. 117,454 residents work from home.
152,084 members of the workforce hold a high school diploma or GED. 71,576 have associates degrees, 250,760 have bachelor’s degrees, and 152,151 hold a graduate or professional degree.
Source: ESRI, 2026-08-31
