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Rock County, WI
11 cities and towns and 11 ZIP codes in Rock County, Wisconsin.
Population
164,350
Land area
718sq mi
People per sq mi
229
ZIP codes
11
Cities and towns in Rock County
Rock County at a glance
- Rock County is about 2.1 times as dense as Wisconsin as a whole.
- By population, it ranks 9th among 72 counties in Wisconsin.
- The median household income is $75,673, close to the Wisconsin median.
- A typical owner-occupied home is valued at $231,600 (13% below Wisconsin) and median rent is $1,037 a month.
- Its largest cities are Janesville (66,030), Beloit (36,534) and Edgerton (6,014).
Local data for Rock County, WI
Counts from official public data
- Hospitals4
- Emergency Rooms4
- Nursing Homes10
- Schools71
- Colleges4
- Libraries8
- Banks35
- Post Offices12
- Parks134
- Grocery Stores51
- Restaurants451
- Affordable Housing13
- Home Health Agencies1
- Hospice Care2
- Dialysis Centers4
- Community Health Centers2
- Mental Health & Addiction Treatment10
- Private Schools9
- Community Colleges & Trade Schools3
- Superfund Sites3
- Toxic Release Facilities23
- Historic Places116
Housing and community stats
Rock County, WI, American Community Survey 2020-2024
Median household income
$75,673
Poverty rate
9.3%
Median home value
$231,600
Prices +5.1% in a year
Median rent
$1,037/mo
Homeownership
71.2%
Bachelor's or higher
25.8%
Median age
40.3
Average commute
23.8 min
Largest reported origins and ancestries: German Americans (51,874), Irish Americans (21,418), Norwegian Americans (16,241).
Economy and federal money
Jobs, income, federal spending and pandemic loans
Unemployment rate
3.0%
Sep 2026, +0.1 pts in a year
Average annual pay
$62,479
69,744 jobs, 2025
Income per person
$58,844
BEA, 2024
Federal spending
$1.4B
FY 2026, $8,311 per person
PPP loans
$260M
3,874 loans, 32,146 jobs reported
Campaign donations
$26.2M
Itemized, 2026 cycle
How people get to work
Rock County, WI, workers 16 and older. American Community Survey 5-year estimates
- Drove alone80.1%
- Carpooled7.2%
- Public transit0.5%
- Walked1.7%
- Bicycle0.1%
- Taxi, ride-hailing, motorcycle or other1.2%
- Worked from home9.2%
Average one-way commute: 23.8 minutes for people who do not work from home.
Environment and hazard risk
Rock County, WI, from FEMA, NOAA and EPA
Natural hazard risk
Relatively Moderate
Top: hail
Storm events since 1996
1,089
Most often thunderstorm wind
Flood insurance policies
221
0.4% of homes, county
July high / Jan low
83° / 12°F
37.4 inches of rain a year
Hazards, floods and storm historyCheck a flood zone116 historic places
Health statistics
Share of adults in Rock County, WI, CDC PLACES estimates
Obesity
41.9%
U.S. 33.3% +8.6 pts
Diabetes
12.3%
U.S. 12.1% about the same
Smoking
14.7%
U.S. 12.8% +1.9 pts
Uninsured (18-64)
8.8%
U.S. 11.1% -2.3 pts
Cities, towns and ZIP codes in Rock County
Population shown
Frequently asked questions
- What is the largest city in Rock County, WI?
- Janesville is the largest city or town in Rock County, with about 66,030 residents.
- How many ZIP codes are in Rock County?
- Rock County includes 11 ZIP Code Tabulation Areas, including 53501, 53505, 53511, 53525, 53536.
- What is the population of Rock County, WI?
- About 164,350 people live in Rock County, based on American Community Survey 5-year estimates.
- What counties border Rock County?
- Rock County borders Dane County, Winnebago County, IL, Walworth County, Jefferson County, Boone County, IL, Green County.
Source: U.S. Census Bureau (TIGER/Line boundaries, American Community Survey) · Data as of 12/31/2023