Oldest ZIP codes in Knox County, IL
These are the 10 ZIP codes in Knox County with the highest median age, out of 10 with at least 1,000 residents. 61428 (Dahinda, 53.0), 61490 (Woodhull, 50.2) and 61448 (Knoxville, 45.2) lead the list. There is no single "best" ZIP code in Knox 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 Knox County
| Rank | ZIP | Mailing city | Median age | Residents | Households | Residential mailboxes |
|---|---|---|---|---|---|---|
| 1 | 61428 | Dahinda | 53.0 ±12.2 | 1,278 | 542 | 564 |
| 2 | 61490 | Woodhull | 50.2 ±6.2 | 1,035 | 509 | 257 |
| 3 | 61448 | Knoxville | 45.2 ±4.1 | 3,947 | 1,736 | 1,571 |
| 4 | 61402 | Galesburg | 42.3 ±1.3 | 1,623 | 0 | — |
| 5 | 61401 | Galesburg | 41.2 ±1.4 | 30,580 | 13,694 | — |
| 6 | 61434 | Galva | 40.7 ±6.2 | 2,971 | 1,207 | 1,360 |
| 7 | 61488 | Wataga | 40.5 ±11.8 | 1,084 | 486 | 310 |
| 8 | 61531 | Farmington | 39.2 ±3.7 | 3,007 | 1,221 | — |
| 9 | 61467 | Oneida | 39.0 ±10.2 | 1,159 | 393 | — |
| 10 | 61410 | Abingdon | 38.3 ±5.3 | 3,838 | 1,663 | 1,548 |
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; 10 of 22 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 16,481 households. Open any of them on the route map to see each carrier route's own figures before you choose.
Open 61428 on the EDDM route map
More rankings
- Richest ZIP codes in Knox County
- ZIP codes with the highest home values in Knox County
- ZIP codes with the highest homeownership in Knox County
- ZIP codes with the most families with kids in Knox County
- ZIP codes with the most new movers in Knox County
- Youngest ZIP codes in Knox County
- Fastest-growing ZIP codes in Knox County
- All Knox County ZIP codes
Businesses that mail these ZIP codes
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EDDM guides
Frequently asked questions
- Which ZIP code in Knox County has the highest median age?
- 61428 (Dahinda), at 53.0 (±12.2), among 10 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.