Oldest ZIP codes in New Castle County, DE
These are the 24 ZIP codes in New Castle County with the highest median age, out of 24 with at least 1,000 residents. 21912 (Warwick, 58.2), 19807 (Wilmington, 54.0) and 19806 (Wilmington, 50.3) lead the list. There is no single "best" ZIP code in New Castle 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 New Castle County
| Rank | ZIP | Mailing city | Median age | Residents | Households | Residential mailboxes |
|---|---|---|---|---|---|---|
| 1 | 21912 | Warwick | 58.2 ±7.7 | 1,536 | 696 | 466 |
| 2 | 19807 | Wilmington | 54.0 ±4.4 | 7,815 | 3,555 | 3,831 |
| 3 | 19806 | Wilmington | 50.3 ±4.5 | 9,777 | 6,033 | 6,349 |
| 4 | 19803 | Wilmington | 46.4 ±2.4 | 22,279 | 8,679 | 8,959 |
| 5 | 19707 | Hockessin | 46.0 ±4.0 | 17,376 | 6,448 | 6,591 |
| 6 | 19810 | Wilmington | 45.3 ±1.6 | 26,530 | 10,655 | 10,813 |
| 7 | 19808 | Wilmington | 42.6 ±1.5 | 39,082 | 15,544 | 16,695 |
| 8 | 19701 | Bear | 42.1 ±1.9 | 42,984 | 16,599 | 16,507 |
| 9 | 19804 | Wilmington | 41.5 ±1.9 | 18,779 | 7,677 | 7,432 |
| 10 | 19706 | Delaware City | 40.4 ±3.6 | 2,038 | 758 | — |
| 11 | 19709 | Middletown | 40.2 ±1.7 | 53,234 | 18,608 | 21,477 |
| 12 | 19720 | New Castle | 39.7 ±1.3 | 62,392 | 23,641 | 23,179 |
| 13 | 19938 | Clayton | 39.4 ±2.7 | 9,561 | 3,159 | 3,561 |
| 14 | 19713 | Newark | 39.0 ±1.8 | 30,747 | 12,526 | 13,188 |
| 15 | 19703 | Claymont | 39.0 ±3.1 | 15,460 | 6,974 | 7,192 |
| 16 | 19809 | Wilmington | 38.6 ±3.4 | 14,311 | 6,121 | 6,605 |
| 17 | 19977 | Smyrna | 38.1 ±2.3 | 27,704 | 9,322 | 11,076 |
| 18 | 19734 | Townsend | 37.5 ±2.9 | 14,214 | 4,534 | 5,064 |
| 19 | 19702 | Newark | 37.2 ±1.6 | 55,683 | 21,252 | 21,813 |
| 20 | 19802 | Wilmington | 36.8 ±2.3 | 26,051 | 10,478 | 10,665 |
| 21 | 19805 | Wilmington | 35.5 ±1.4 | 41,402 | 15,722 | 16,115 |
| 22 | 19801 | Wilmington | 35.3 ±2.1 | 16,327 | 8,150 | 9,442 |
| 23 | 19711 | Newark | 34.7 ±1.1 | 49,432 | 18,815 | 21,334 |
| 24 | 19717 | Newark | 19.3 ±0.2 | 6,036 | 0 | 32 |
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; 24 of 32 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 25,411 households, on 62 carrier routes with 26,196 residential mailboxes. Open any of them on the route map to see each carrier route's own figures before you choose.
Open 21912 on the EDDM route map
More rankings
- Richest ZIP codes in New Castle County
- ZIP codes with the highest home values in New Castle County
- ZIP codes with the highest homeownership in New Castle County
- ZIP codes with the most families with kids in New Castle County
- ZIP codes with the most new movers in New Castle County
- Youngest ZIP codes in New Castle County
- Fastest-growing ZIP codes in New Castle County
- All New Castle County ZIP codes
Businesses that mail these ZIP codes
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EDDM guides
Frequently asked questions
- Which ZIP code in New Castle County has the highest median age?
- 21912 (Warwick), at 58.2 (±7.7), among 24 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.