Oldest ZIP codes in Union County, PA
These are the 7 ZIP codes in Union County with the highest median age, out of 7 with at least 1,000 residents. 17856 (New Columbia, 46.4), 17845 (Millmont, 46.2) and 17889 (Winfield, 43.9) lead the list. There is no single "best" ZIP code in Union 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 Union County
| Rank | ZIP | Mailing city | Median age | Residents | Households | Residential mailboxes |
|---|---|---|---|---|---|---|
| 1 | 17856 | New Columbia | 46.4 ±8.2 | 3,167 | 1,339 | 1,474 |
| 2 | 17845 | Millmont | 46.2 ±4.4 | 2,058 | 775 | 968 |
| 3 | 17889 | Winfield | 43.9 ±2.7 | 3,039 | 1,125 | 1,141 |
| 4 | 17855 | New Berlin | 42.7 ±3.6 | 1,014 | 394 | 199 |
| 5 | 17844 | Mifflinburg | 40.1 ±4.8 | 10,291 | 4,250 | 4,050 |
| 6 | 17810 | Allenwood | 39.2 ±3.2 | 5,309 | 607 | 766 |
| 7 | 17837 | Lewisburg | 37.4 ±2.5 | 18,403 | 5,969 | 6,686 |
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; 7 of 13 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 7,883 households, on 16 carrier routes with 7,832 residential mailboxes. Open any of them on the route map to see each carrier route's own figures before you choose.
Open 17856 on the EDDM route map
More rankings
- Richest ZIP codes in Union County
- ZIP codes with the highest home values in Union County
- ZIP codes with the highest homeownership in Union County
- ZIP codes with the most families with kids in Union County
- ZIP codes with the most new movers in Union County
- Youngest ZIP codes in Union County
- Fastest-growing ZIP codes in Union County
- All Union County ZIP codes
Businesses that mail these ZIP codes
Map it and price it
EDDM guides
Frequently asked questions
- Which ZIP code in Union County has the highest median age?
- 17856 (New Columbia), at 46.4 (±8.2), among 7 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.