Oldest ZIP codes in LaSalle County, IL
These are the 16 ZIP codes in LaSalle County with the highest median age, out of 16 with at least 1,000 residents. 60552 (Somonauk, 48.6), 61354 (Peru, 46.2) and 61377 (Wenona, 44.3) lead the list. There is no single "best" ZIP code in LaSalle 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 LaSalle County
| Rank | ZIP | Mailing city | Median age | Residents | Households | Residential mailboxes |
|---|---|---|---|---|---|---|
| 1 | 60552 | Somonauk | 48.6 ±6.8 | 4,285 | 1,807 | 1,557 |
| 2 | 61354 | Peru | 46.2 ±3.2 | 10,290 | 4,682 | 4,892 |
| 3 | 61377 | Wenona | 44.3 ±9.0 | 1,441 | 699 | — |
| 4 | 61373 | Utica | 42.7 ±5.1 | 2,123 | 802 | — |
| 5 | 61341 | Marseilles | 42.5 ±2.0 | 7,692 | 3,098 | — |
| 6 | 60551 | Sheridan | 42.3 ±3.7 | 5,058 | 1,546 | 1,179 |
| 7 | 61350 | Ottawa | 42.2 ±1.6 | 23,713 | 9,756 | 10,903 |
| 8 | 61364 | Streator | 41.9 ±1.8 | 17,963 | 8,094 | 8,122 |
| 9 | 60518 | Earlville | 41.9 ±4.7 | 3,289 | 1,465 | 1,255 |
| 10 | 61301 | La Salle | 41.7 ±3.2 | 10,398 | 4,579 | — |
| 11 | 61342 | Mendota | 41.5 ±2.8 | 8,543 | 3,487 | 3,545 |
| 12 | 61348 | Oglesby | 41.5 ±4.1 | 4,375 | 1,943 | 2,113 |
| 13 | 61370 | Tonica | 41.2 ±3.2 | 1,215 | 471 | 416 |
| 14 | 60548 | Sandwich | 40.8 ±3.2 | 11,721 | 4,548 | 5,002 |
| 15 | 60531 | Leland | 38.2 ±2.5 | 1,885 | 724 | 547 |
| 16 | 61360 | Seneca | 37.9 ±10.2 | 3,610 | 1,363 | 1,032 |
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; 16 of 28 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 11,088 households. Open any of them on the route map to see each carrier route's own figures before you choose.
Open 60552 on the EDDM route map
More rankings
- Richest ZIP codes in LaSalle County
- ZIP codes with the highest home values in LaSalle County
- ZIP codes with the highest homeownership in LaSalle County
- ZIP codes with the most families with kids in LaSalle County
- ZIP codes with the most new movers in LaSalle County
- Youngest ZIP codes in LaSalle County
- Fastest-growing ZIP codes in LaSalle County
- All LaSalle County ZIP codes
Businesses that mail these ZIP codes
Map it and price it
EDDM guides
Frequently asked questions
- Which ZIP code in LaSalle County has the highest median age?
- 60552 (Somonauk), at 48.6 (±6.8), among 16 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.