Oldest ZIP codes in Cerro Gordo County, IA
These are the 6 ZIP codes in Cerro Gordo County with the highest median age, out of 6 with at least 1,000 residents. 50428 (Clear Lake, 50.5), 50469 (Rockwell, 47.2) and 50458 (Nora Springs, 44.6) lead the list. There is no single "best" ZIP code in Cerro Gordo 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 Cerro Gordo County
| Rank | ZIP | Mailing city | Median age | Residents | Households | Residential mailboxes |
|---|---|---|---|---|---|---|
| 1 | 50428 | Clear Lake | 50.5 ±3.2 | 9,071 | 4,186 | 5,169 |
| 2 | 50469 | Rockwell | 47.2 ±9.9 | 1,527 | 635 | — |
| 3 | 50458 | Nora Springs | 44.6 ±2.0 | 2,094 | 794 | 592 |
| 4 | 50475 | Sheffield | 43.8 ±6.4 | 1,446 | 596 | — |
| 5 | 50401 | Mason City | 42.2 ±1.2 | 28,703 | 13,321 | — |
| 6 | 50468 | Rockford | 40.5 ±4.0 | 1,617 | 653 | 591 |
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; 6 of 14 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 19,532 households. Open any of them on the route map to see each carrier route's own figures before you choose.
Open 50428 on the EDDM route map
More rankings
- Richest ZIP codes in Cerro Gordo County
- ZIP codes with the highest home values in Cerro Gordo County
- ZIP codes with the highest homeownership in Cerro Gordo County
- ZIP codes with the most families with kids in Cerro Gordo County
- ZIP codes with the most new movers in Cerro Gordo County
- Youngest ZIP codes in Cerro Gordo County
- Fastest-growing ZIP codes in Cerro Gordo County
- All Cerro Gordo County ZIP codes
Businesses that mail these ZIP codes
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EDDM guides
Frequently asked questions
- Which ZIP code in Cerro Gordo County has the highest median age?
- 50428 (Clear Lake), at 50.5 (±3.2), among 6 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.