Which ZIP code in Rock County has the highest median age?

53576 (Orfordville), at 46.6 (±5.1), among 12 ZIP codes with at least 1,000 residents.

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.

Oldest ZIP codes in Rock County, WI

These are the 12 ZIP codes in Rock County with the highest median age, out of 12 with at least 1,000 residents. 53576 (Orfordville, 46.6), 53114 (Darien, 45.0) and 53520 (Brodhead, 44.6) lead the list. There is no single "best" ZIP code in Rock 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 Rock County

Rank	ZIP	Mailing city	Median age	Residents	Households	Residential mailboxes
1	53576	Orfordville	46.6 ±5.1	2,131	943	856
2	53114	Darien	45.0 ±6.3	1,979	809	884
3	53520	Brodhead	44.6 ±2.6	6,687	2,914	2,867
4	53525	Clinton	43.9 ±6.2	4,066	1,641	—
5	53548	Janesville	43.3 ±3.3	19,916	8,562	8,147
6	53563	Milton	42.5 ±2.8	11,280	4,632	—
7	53546	Janesville	41.0 ±1.7	29,867	12,314	13,419
8	53545	Janesville	40.8 ±2.2	24,703	10,909	—
9	53534	Edgerton	40.1 ±2.2	12,241	4,808	6,179
10	53536	Evansville	38.8 ±2.7	9,547	4,116	3,822
11	53511	Beloit	37.0 ±1.1	48,701	18,392	—
12	53190	Whitewater	23.7 ±0.8	20,499	7,126	7,255

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; 12 of 15 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 14,869 households. Open any of them on the route map to see each carrier route's own figures before you choose.

Open 53576 on the EDDM route map

More rankings

Businesses that mail these ZIP codes

Map it and price it

EDDM guides

Frequently asked questions

Which ZIP code in Rock County has the highest median age?: 53576 (Orfordville), at 46.6 (±5.1), among 12 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.