Oldest ZIP codes in Contra Costa County, CA
These are the 25 ZIP codes in Contra Costa County with the highest median age, out of 43 with at least 1,000 residents. 94595 (Walnut Creek, 69.2), 94511 (Bethel Island, 56.6) and 94707 (Berkeley, 52.9) lead the list. There is no single "best" ZIP code in Contra Costa County; the right one depends on who you want to reach, so the same ZIP codes are ranked several ways below.
Oldest ZIP codes in Contra Costa County
| Rank | ZIP | Mailing city | Median age | Residents | Households | Residential mailboxes |
|---|---|---|---|---|---|---|
| 1 | 94595 | Walnut Creek | 69.2 ±1.9 | 16,988 | 9,368 | 10,249 |
| 2 | 94511 | Bethel Island | 56.6 ±15.2 | 1,864 | 863 | — |
| 3 | 94707 | Berkeley | 52.9 ±2.2 | 12,811 | 5,267 | 5,191 |
| 4 | 94507 | Alamo | 49.5 ±2.8 | 14,586 | 5,098 | 5,496 |
| 5 | 94708 | Berkeley | 48.6 ±2.1 | 11,947 | 4,800 | 4,846 |
| 6 | 94525 | Crockett | 47.5 ±4.6 | 3,372 | 1,539 | 1,621 |
| 7 | 94563 | Orinda | 47.4 ±2.4 | 19,378 | 7,218 | 7,247 |
| 8 | 94549 | Lafayette | 46.3 ±1.4 | 28,420 | 10,682 | 11,250 |
| 9 | 94526 | Danville | 46.0 ±1.5 | 32,584 | 11,843 | 12,489 |
| 10 | 94598 | Walnut Creek | 45.9 ±2.4 | 27,206 | 10,828 | 10,876 |
| 11 | 94505 | Discovery Bay | 45.8 ±3.2 | 14,970 | 5,446 | 5,987 |
| 12 | 94514 | Byron | 45.7 ±12.9 | 1,953 | 576 | 218 |
| 13 | 94506 | Danville | 45.3 ±1.5 | 27,055 | 9,185 | 8,802 |
| 14 | 94564 | Pinole | 44.7 ±1.6 | 18,761 | 6,588 | 7,246 |
| 15 | 94547 | Hercules | 43.9 ±1.8 | 26,302 | 9,355 | 9,220 |
| 16 | 94805 | Richmond | 43.0 ±2.4 | 14,670 | 5,493 | 5,258 |
| 17 | 94517 | Clayton | 43.0 ±2.5 | 12,316 | 4,511 | 4,615 |
| 18 | 94528 | Diablo | 43.0 ±18.1 | 1,049 | 424 | — |
| 19 | 94521 | Concord | 42.9 ±1.3 | 41,909 | 15,938 | 16,116 |
| 20 | 94553 | Martinez | 42.6 ±1.0 | 48,643 | 19,141 | 20,109 |
| 21 | 94556 | Moraga | 42.4 ±1.7 | 15,998 | 5,614 | 6,003 |
| 22 | 94582 | San Ramon | 42.3 ±1.1 | 47,424 | 16,466 | 16,067 |
| 23 | 94803 | El Sobrante | 42.3 ±2.0 | 27,659 | 9,562 | 9,620 |
| 24 | 94523 | Pleasant Hill | 42.0 ±1.1 | 34,592 | 13,452 | 14,705 |
| 25 | 94530 | El Cerrito | 41.8 ±1.4 | 26,401 | 11,021 | 11,153 |
How we ranked them
Ranked by median age of all residents, highest first (ACS 5-year estimates, 2020–2024). ZIP codes need at least 1,000 residents to be ranked; 43 of 47 qualify.
Which of these to mail, and why
Older ZIP codes respond to health care, hearing and vision, Medicare plans, home safety, estate planning and services that come to the door.
The top five ZIP codes on this list hold 25,396 households. Open any of them on the route map to see each carrier route's own figures before you choose.
Open 94595 on the EDDM route map
More rankings
- Richest ZIP codes in Contra Costa County
- ZIP codes with the highest home values in Contra Costa County
- ZIP codes with the highest homeownership in Contra Costa County
- ZIP codes with the most families with kids in Contra Costa County
- ZIP codes with the most new movers in Contra Costa County
- Youngest ZIP codes in Contra Costa County
- Fastest-growing ZIP codes in Contra Costa County
- All Contra Costa County ZIP codes
Businesses that mail these ZIP codes
Map it and price it
EDDM guides
Frequently asked questions
- Which ZIP code in Contra Costa County has the highest median age?
- 94595 (Walnut Creek), at 69.2 (±1.9), among 43 ZIP codes with at least 1,000 residents.
- How is this ranking calculated?
- Ranked by median age of all residents, highest first (ACS 5-year estimates, 2020–2024).
- Why are some ZIP codes missing?
- ZIP codes with fewer than 1,000 residents are left out because their survey estimates swing too much to rank, and so are ZIP codes where the Census Bureau did not publish this figure.
This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.