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Where am ILOCATED

Contra Costa County, California

Contra Costa County, California, has 1,170,070 residents (July 2025 estimate). Its county seat is Martinez. It uses Pacific Time and covers 717 sq mi (1,857 km²) of land.

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Contra Costa County in California
ConcordAntiochRichmondSan RamonPittsburg
Contra Costa County and its neighbors (simplified outlines). Open in OpenStreetMap ↗
Resident population, July 2025
1,170,070
Land area
717 sq mi (1,857 km²)
County seat or government
Martinez
Time zone
Pacific TimeUTC-08:00 in January; UTC-07:00 in July
Median household income
$127,229 ± $1,713
Median home value
$866,800 ± $6,426
Median rent, with utilities
$2,375 ± $22
Homes lived in by their owners
68% ± 0.5 points
County type
County
Metro or micro area
San Francisco-Oakland-Fremont, CA metro areaOutlying county
Water area
87 sq mi (225 km²)
State
California
County code (FIPS)
06013
Coordinates (central point)
37.919479, -121.951543
Open this point in the location finder

These coordinates mark a central point for the area, not a street address. Income, home value, rent and homes lived in by their owners: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, ± margin at 90% confidence; checked on October 13, 2026.

Time zones in Contra Costa County

Time zoneLocal time and UTC offsetNext clock change
Pacific TimeAmerica/Los_AngelesUTC-08:00 in January; UTC-07:00 in July. Enable JavaScript for the live clock.Enable JavaScript for upcoming changes.

Near a time-zone line, check where you are with the time-zone finder. Your phone’s setting can differ.

ZIP Code areas, largest first

  1. 94565100,488 people
  2. 9450970,090 people
  3. 9451369,755 people
  4. 9480662,546 people
  5. 9455348,643 people
  6. 9458247,424 people
  7. 9453146,387 people
  8. 9456146,368 people
  9. 9480444,891 people
  10. 9452141,909 people
  11. 9461140,116 people
  12. 9458339,583 people
All 49
  1. 9455137,885 people
  2. 9452037,381 people
  3. 9452334,592 people
  4. 9458834,328 people
  5. 9480133,591 people
  6. 9452632,584 people
  7. 9521931,713 people
  8. 9454928,420 people
  9. 9480327,659 people
  10. 9451827,345 people
  11. 9459827,206 people
  12. 9450627,055 people
  13. 9453026,401 people
  14. 9454726,302 people
  15. 9459623,417 people
  16. 9459723,129 people
  17. 9470619,969 people
  18. 9456319,378 people
  19. 9451919,058 people
  20. 9456418,761 people
  21. 9459516,988 people
  22. 9455615,998 people
  23. 9450514,970 people
  24. 9480514,670 people
  25. 9450714,586 people
  26. 9470712,811 people
  27. 9451712,316 people
  28. 9470811,947 people
  29. 945728,976 people
  30. 945253,372 people
  31. 945141,953 people
  32. 945111,864 people
  33. 945281,049 people
  34. 94575975 people
  35. 94548832 people
  36. 94569296 people
  37. 94516214 people

49 ZIP Code areas overlap Contra Costa County. People counts are 2020–2024 estimates for each whole ZIP area. Mailing ZIPs can differ; check an address with USPS ZIP Code Lookup.

Official county information

We don’t have a website for this county yet. The US government’s local-office directory ↗ lists its offices. A geographic lookup cannot determine eligibility, tax liability or a court obligation.

School districts in Contra Costa County, largest first

  1. Mount Diablo Unified School District262,655 people
  2. West Contra Costa Unified School District258,797 people
  3. San Ramon Valley Unified School District163,204 people
  4. Liberty Union High School District134,376 people
  5. Antioch Unified School District119,092 people
  6. Acalanes Union High School District118,735 people
  7. Livermore Valley Joint Unified School District88,347 people
  8. Brentwood Union Elementary School District71,825 people
  9. Pittsburg Unified School District64,372 people
  10. Walnut Creek Elementary School District53,787 people
  11. Oakley Union Elementary School District42,584 people
  12. Martinez Unified School District29,787 people
All 19
  1. Lafayette Elementary School District28,383 people
  2. Orinda Union Elementary School District19,378 people
  3. Moraga Elementary School District16,973 people
  4. Byron Union Elementary School District15,586 people
  5. John Swett Unified School District13,884 people
  6. Knightsen Elementary School District4,381 people
  7. Canyon Elementary School District214 people

Districts with land in the county; a district can cross county lines. People counts are American Community Survey 2020–2024 5-year estimates. A district boundary doesn’t decide which school a student attends.

Tribal areas in Contra Costa County, largest first

  1. Lytton Rancheria0 people

American Indian, Alaska Native and Native Hawaiian areas as the Census Bureau maps them, with at least 2% of their area here, water included. These lines don’t decide membership, jurisdiction or land status.

Cities, towns and communities, largest first

These areas overlap the mapped boundary; an overlap does not mean that every address belongs to both.

  1. Concord, California (city)124,035 people
  2. Antioch, California (city)116,477 people
  3. Richmond, California (city)115,505 people
  4. San Ramon, California (city)85,993 people
  5. Pittsburg, California (city)76,257 people
  6. Walnut Creek, California (city)70,088 people
  7. Brentwood, California (city)65,208 people
  8. Oakley, California (city)45,183 people
  9. Danville, California (town)43,401 people
  10. Martinez, California (city)36,903 people
  11. Pleasant Hill, California (city)34,235 people
  12. San Pablo, California (city)31,720 people
All 53
  1. Hercules, California (city)26,302 people
  2. El Cerrito, California (city)25,994 people
  3. Lafayette, California (city)25,285 people
  4. Bay Point, California (CDP)24,231 people
  5. Orinda, California (city)19,514 people
  6. Pinole, California (city)18,761 people
  7. Moraga, California (town)16,769 people
  8. El Sobrante, Contra Costa County, California (CDP)16,294 people
  9. Discovery Bay, California (CDP)14,911 people
  10. Alamo, California (CDP)14,488 people
  11. Clayton, California (city)10,937 people
  12. Blackhawk, California (CDP)10,137 people
  13. Rodeo, California (CDP)8,976 people
  14. Contra Costa Centre, California (CDP)6,893 people
  15. Camino Tassajara, California (CDP)5,831 people
  16. Saranap, California (CDP)5,662 people
  17. Kensington, California (CDP)5,179 people
  18. Tara Hills, California (CDP)4,840 people

See all 53 cities, towns and communities in Contra Costa County, largest first

Bordering areas, nearest first

Distances are straight lines between map points.

  1. Alameda County, California19 mi south
  2. Solano County, California24 mi north
  3. San Joaquin County, California37 mi east
  4. Marin County, California44 mi west
  5. Sacramento County, California49 mi northeast
  6. San Francisco County, California60 mi west
  7. Sonoma County, California67 mi northwest

Before using this answer on a form

Use a precise point for address-level questions. A device accuracy circle can cross a boundary; confirm tax, voting or jury details with the responsible office.

Find the county where you are now, check its ZIP area, or check the time zone where you are.

See this county on Census.gov ↗

Areas that only touch the edge

These areas meet the boundary only along a sliver. Most addresses here are not in them; for an address near the line, check with the county.