County · Wisconsin
Rock County, Wisconsin
Rock County, Wisconsin. Rock County had 166,472 residents in 2025 by the Census Bureau's estimate, up 1.7% since 2020, in line with Wisconsin (+1.3%). It holds 32 places (9 cities, villages and boroughs, 20 towns and townships and 3 census-designated) and 41 census tracts. GEOID 55105.
Rock County is the county of the Janesville-Beloit, WI metropolitan statistical area (the Census Bureau's July 2023 delineation).
Residents, July 2025 estimate
166,472
Census Bureau estimate (no margin published)
2020 Census count: 163,687 · ACS 2020-2024: 164,350
Median household income
$75,673
±$2,128 (90% margin)
Wisconsin: $77,485
Median home value
$231,600
±$3,637 (90% margin)
Wisconsin: $266,500
Median gross rent
$1,037
±$27 (90% margin)
Wisconsin: $1,087
How many people live in Rock County, and is it growing?
The 2020 Census counted 163,687 residents in Rock County. The Census Bureau estimates 166,472 for July 1, 2025, up 1.7% since 2020, in line with Wisconsin (+1.3%). The 2020-2024 American Community Survey puts the population at 164,350 over 718 square miles of land.
| Measure | Rock County | Wisconsin | Change since 2015-2019 |
|---|---|---|---|
| Total population | 164,350 | 5,914,872 | +2,198 |
| Households | 67,201±481 | 2,479,480 | +2,462 |
| Average household size | 2.41±0.02 | 2.33 | −0.05 |
| Housing units | 71,109±90 | 2,778,572 | +2,081 |
Rock County's population since 2000
From 152,307 in 2000 to 166,472 in 2025: up 9.3%. The 2000, 2010 and 2020 figures are census counts. The 2005 figure is the Census Bureau's intercensal estimate, revised to fit the 2000 and 2010 counts and drawn on 2010 boundaries; 2015 and 2025 are July 1 estimates made from the census before them.
Source: The 2000, 2010 and 2020 Census counts and the Census Bureau's population estimates (intercensal 2000-2010, Vintage 2020, Vintage 2025) · Census population estimates
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); PEP Vintage 2025 (CO-EST2025); 2020 Census · Check it at data.census.gov
What cities and towns are in Rock County?
Rock County holds 32 places: 9 cities, villages and boroughs (incorporated places), 20 towns and townships (county subdivisions with their own government) and 3 census-designated places. The largest is Janesville with 66,929 residents (2025 estimate). Places that cross a county line are listed with the share of their 2020 residents who live in this county.
| Janesville | 65,615 | $73,446 |
|---|---|---|
| Beloit | 36,657 | $62,663 |
| Beloit (town) | 7,721 | $79,662 |
| Edgerton | 5,945 | $72,489 |
| Milton | 5,716 | $85,959 |
| Evansville | 5,703 | $81,149 |
| Janesville (town) | 3,665 | $102,660 |
| Fulton (town) | 3,580 | $101,336 |
| Milton (town), Rock County | 3,100 | $106,667 |
| Rock (town), Rock County | 2,981 | $71,065 |
| Harmony (town), Rock County | 2,569 | $122,852 |
| Turtle (town) | 2,393 | $93,750 |
| Clinton | 2,221 | $72,019 |
| Union (town), Rock County | 2,104 | $99,279 |
| Newark (town) | 1,510 | $95,667 |
| Orfordville | 1,473 | $65,417 |
| Lima (town), Rock County | 1,271 | $65,139 |
| Plymouth (town), Rock County | 1,245 | $85,598 |
| Center (town), Rock County | 1,046 | $112,222 |
| Bradford (town) | 1,013 | $115,833 |
| Porter (town) | 969 | $95,833 |
| Clinton (town), Rock County | 889 | $97,500 |
| La Prairie (town) | 784 | $80,781 |
| Footville | 772 | $68,571 |
| Johnstown (town), Rock County | 766 | $84,609 |
| Magnolia (town) | 742 | $71,250 |
| Spring Valley (town) | 728 | $70,938 |
| Avon (town)GEOID 5510504100 | 570 | $91,653 |
| HanoverGEOID 5532550 | 179 | $60,972 |
| ShopiereGEOID 5573675 | 154 | not published |
| FultonGEOID 5528050 | 117 | not published |
| Brodhead | 3,274 | $49,583 |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 place-by-county parts · Check it at data.census.gov
Who lives in Rock County?
The median resident of Rock County is 40.3 years old; 22.4% are under 18 and 17.8% are 65 or older. The largest group is non-Hispanic white residents at 79.6%, then Hispanic or Latino residents (of any race) at 10.1%. 4.6% of residents were born outside the United States.
| Measure | Rock County | Wisconsin | Change since 2015-2019 |
|---|---|---|---|
| Median age | 40.3±0.3 | 40.2 | +0.8 |
| Under 18 years | 22.4% | 21.4% | – |
| 65 years and over | 17.8%±0.1 pts | 18.5% | – |
| Hispanic or Latino (any race) | 10.1% | 8.0% | +1.4 pts |
| White alone, not Hispanic | 79.6%±0.4 pts | 78.6% | −3.2 pts |
| Black or African American alone, not Hispanic | 4.6%±0.4 pts | 5.9% | no clear change |
| Asian alone, not Hispanic | 1.1%±0.1 pts | 2.9% | no clear change |
| American Indian and Alaska Native alone, not Hispanic | 0.0%±0.1 pts | 0.5% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0%±0.1 pts | 0.0% | – |
| Two or more races, not Hispanic | 4.2%±0.5 pts | 3.7% | – |
| Some other race alone, not Hispanic | 0.3%±0.1 pts | 0.3% | – |
| Born outside the United States | 4.6%±0.4 pts | 5.2% | no clear change |
| Speak a language other than English at home (age 5+) | 8.8%±0.6 pts | 9.0% | – |
| Civilian veterans (age 18+) | 6.9%±0.5 pts | 6.2% | – |
| With a disability | 12.8%±0.6 pts | 12.3% | – |
| No health insurance coverage | 5.5%±0.6 pts | 5.2% | no clear change |
| High school graduate or higher (age 25+) | 92.6%±0.6 pts | 93.6% | – |
| Bachelor's degree or higher (age 25+) | 25.8%±1.0 pts | 33.4% | +3.7 pts |
| Graduate or professional degree (age 25+) | 8.1%±0.7 pts | 11.4% | – |
| Moved from another state in the past year | 1.9%±0.4 pts | 2.0% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profiles DP02, DP05) · Check it at data.census.gov
What do households in Rock County earn?
Half of Rock County's 67,201 households earn less than $75,673 a year (±$2,128), against $77,485 in Wisconsin. In 2015-2019 the median was $71,226 in 2024 dollars, so it rose by $4,447 after inflation. 9.3% of residents live below the poverty line.
| Measure | Rock County | Wisconsin | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $75,673±$2,128 | $77,485 | +$4,447 |
| Mean household income | $91,984±$2,382 | $101,466 | – |
| Per capita income | $38,536±$1,081 | $43,373 | +$2,914 |
| People below the poverty line | 9.3%±0.7 pts | 10.6% | −3.5 pts |
| Children under 18 below the poverty line | 12.9%±2.0 pts | 12.8% | −6.7 pts |
| Households receiving SNAP | 12.9%±1.1 pts | 11.1% | – |
| Households with a broadband subscription | 90.3%±1.1 pts | 90.3% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What does housing cost in Rock County?
Owners occupy 71.2% of Rock County's occupied homes and renters 28.8%. The median owner-occupied home is valued at $231,600 by its owner (±$3,637). The median renter pays $1,037 a month including utilities, and 35.0% of renters pay 35% or more of their income on rent.
| Measure | Rock County | Wisconsin | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $231,600±$3,637 | $266,500 | +$51,673 |
| Median gross rent | $1,037±$27 | $1,087 | no clear change |
| Renters paying 35% or more of income on rent | 35.0%±2.8 pts | 35.0% | no clear change |
| Median monthly owner costs, with a mortgage | $1,538±$32 | $1,689 | – |
| Owner-occupied homes | 71.2%±1.2 pts | 67.8% | +2.8 pts |
| Housing units | 71,109±90 | 2,778,572 | +2,081 |
| Homeowner vacancy rate | 1.0%±0.5 pts | 0.5% | – |
| Rental vacancy rate | 3.7%±1.2 pts | 4.5% | – |
| Single-family detached homes | 74.4%±1.0 pts | 66.2% | – |
| Mobile homes | 2.6%±0.5 pts | 3.1% | – |
| Built 2020 or later | 1.2%±0.3 pts | 1.4% | – |
| Built 1939 or earlier | 19.2%±1.0 pts | 17.8% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP04) · Check it at data.census.gov
How many new homes is Rock County building?
Builders took permits for 388 new housing units across Rock County in 2025 (316 single-family), 2.3 per 1,000 residents.
Source: Building Permits Survey, annual county files 2019-2025, U.S. Census Bureau · Census Building Permits Survey
How do people in Rock County get to work?
80.1% of Rock County's workers drive alone and 9.2% work from home. The average trip to work takes 23.8 minutes. The unemployment rate in 2020-2024 averaged 3.8%.
| Measure | Rock County | Wisconsin | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 65.2%±0.9 pts | 65.3% | – |
| Unemployment rate | 3.8%±0.5 pts | 3.2% | −1.3 pts |
| Drove alone to work | 80.1%±1.2 pts | 74.4% | – |
| Carpooled | 7.2%±0.8 pts | 7.3% | – |
| Public transportation | 0.5%±0.2 pts | 1.1% | – |
| Walked | 1.7%±0.3 pts | 2.6% | – |
| Worked from home | 9.2%±0.8 pts | 13.1% | +6.0 pts |
| Mean travel time to work | 23.8 min±0.7 | 22.2 min | +0.9 min |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What are Rock County's census tracts?
Rock County is divided into 41 census tracts. Among those with a reliable estimate, median household income runs from $22,204 (Tract 1) to $124,925 (Tract 13.03).
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) · Check it at data.census.gov
How does Rock County compare with Wisconsin's other counties?
| Measure | Rank |
|---|---|
| Population | 9th of 72 |
| Growth 2020-2025 | 29th of 72 |
| Residents per square mile | 13th of 72 |
| Median household income | 25th of 72 |
| Median home value | 31st of 72 |
| Median gross rent | 16th of 72 |
| Poverty rate | 49th of 72 |
| Bachelor's degree or higher | 33rd of 72 |
| Median age | 56th of 72 |
Source: PlainCities ranks from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) and PEP Vintage 2025 · How ranks are computed
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections
Not on this page: crime, weather and schools for Rock County are other agencies' records. Crime: the FBI's Crime Data Explorer · climate: NOAA's U.S. Climate Normals · schools: the National Center for Education Statistics' school search.