| ZIP Codes: | 15 ZIP Codes (10 Standard, 5 PO Box, 0 Unique) [See All] |
| Area Codes: | 262 / 353 / 608 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 2:14:20 PM |
| Population: | 163,727 [See All] |
| FIPS: | 55105 |
| CBSA: | Janesville-Beloit, WI |
| Land Area: | 663 sq mi |
| Water Area: | 8 sq mi |
| Coordinates: | 42.6699, -89.0550 |
| Quick Link: |
163,727 residents live across 15 ZIPs covering 663 sq mi, served by 11 distinct USPS-recognized cities.
Population moved from 159,605 to 163,727 from 2014 to 2024 — a +2.6% change. 8 ZIPs gained residents, 4 lost.
The county's wealthiest ZIP 53563 (Milton, $89,528 median) and poorest ZIP 53576 (Orfordville, $63,750) are 19.5 miles apart — a 1.4× income gap across local geography.
Median home values vary 1.8× across this county — from $173,500 in 53511 (Beloit) to $304,900 in 53536 (Evansville).
Density varies 16× across the county — from 68 people/sq mi in 53576 (Orfordville) to 1,080 in 53545 (Janesville).
Most of the decade's growth concentrated around Janesville — top growth ZIPs averaged +10.0% over the past ten years ( 53548 , 53545 and 53536 ).
Educational attainment ranges from 19.4% bachelor's+ in 53511 (Beloit) to 34.1% in 53536 (Evansville) — the breadth of educational profiles across the area.
Within Wisconsin, this is the #8 most populous of 73 counties and ranks #29 for median household income .
Weighted by population, the typical household earns about $75,568 across the county — reflecting what a typical resident sees, not a simple ZIP average.
25.8% of adults age 25+ hold a bachelor's degree or higher (29,173 of 113,266 reporting).
10 Standard delivery, 5 PO Box only, 0 single-entity Unique ZIPs serve this county.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 53511 | Beloit | Standard | 48,701 | $67,067 | 115.5 | -0.1% |
| 53546 | Janesville | Standard | 29,867 | $75,825 | 79.5 | -6.8% |
| 53545 | Janesville | Standard | 24,703 | $73,889 | 22.9 | 8.5% |
| 53548 | Janesville | Standard | 19,916 | $76,869 | 75.6 | 13.0% |
| 53534 | Edgerton | Standard | 12,241 | $89,045 | 88.3 | 6.8% |
| 53563 | Milton | Standard | 11,280 | $89,528 | 77.5 | 5.6% |
| 53536 | Evansville | Standard | 9,547 | $87,667 | 89.9 | 8.4% |
| 53525 | Clinton | Standard | 4,066 | $79,323 | 58.7 | 5.5% |
| 53576 | Orfordville | Standard | 2,131 | $63,750 | 31.5 | -11.4% |
| 53537 | Footville | PO Box | 752 | $59,821 | 0.7 | 6.5% |
| 53505 | Avalon | Standard | 358 | $91,500 | 22.1 | -28.1% |
| 53501 | Afton | PO Box | 165 | — | 0.5 | — |
| 53512 | Beloit | PO Box | — | — | 0.0 | — |
| 53542 | Hanover | PO Box | — | — | 0.0 | — |
| 53547 | Janesville | PO Box | — | — | 0.0 | — |