Rock County is a

county A county () is a geographic region of a country used for administrative or other purposesL. Brookes (ed.) '' Chambers Dictionary''. Edinburgh: Chambers Harrap Publishers Ltd, 2005. in some nations. The term is derived from the Old French denoti ...

in the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its so ...

Wisconsin Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...

. As of the 2020 census, the population was 163,687. Its

county seat A county seat is an administrative center, seat of government, or capital city of a county or parish (administrative division), civil parish. The term is in use in five countries: Canada, China, Hungary, Romania, and the United States. An equiva ...

is Janesville. Rock County comprises the Janesville- Beloit, WI Metropolitan Statistical Area and is included in the Madison-Janesville-Beloit, WI Combined Statistical Area.

History

Rock County was created as a territorial county on December 7, 1836, from

Milwaukee County Milwaukee County () is a county located in the U.S. state of Wisconsin. At the 2020 census, the population was 939,489, down from 947,735 in 2010. It is both the most populous and most densely populated county in Wisconsin, containing about 1 ...

and fully organized February 19, 1839. The county is named for the Rock River, which bisects the county from north to south.

Geography

According to the

U.S. Census Bureau The United States Census Bureau, officially the Bureau of the Census, is a principal agency of the U.S. federal statistical system, responsible for producing data about the American people and economy. The U.S. Census Bureau is part of the U ...

, the county has a total area of , of which is land and (1.1%) is water. Cook Memorial Arboretum, a natural area with birding and nature trails, is located northwest of Janesville. It is owned by the Janesville School District.

Transportation

Major highways

Interstate 39 Interstate 39 (I-39) is a north–south Interstate Highway in Illinois and Wisconsin that runs from an interchange at I-55 in Normal, Illinois, to State Trunk Highway 29 (WIS 29) approximately south of Wausau, Wisconsin. In to ...

Interstate 43 Interstate 43 (I-43) is a Interstate Highway located entirely within the US state of Wisconsin, connecting I-39/I-90 in Beloit with Milwaukee and I-41, U.S. Highway 41 (US 41) and US 141 in Green Bay. State Trunk Highw ...

Interstate 90 Interstate 90 (I-90) is an east–west transcontinental freeway and the longest Interstate Highway in the United States at . It begins in Seattle, Washington, and travels through the Pacific Northwest, Mountain states, Mountain West, Great Pla ...

U.S. Highway 12 * US 14

U.S. Highway 14 * US 51

U.S. Highway 51 * WIS 11

Highway 11 * WIS 26

Highway 26 * WIS 59

Highway 59 * WIS 67

Highway 67 * WIS 81

Highway 81 * WIS 89

Highway 89 * WIS 104

Highway 104 * WIS 138

Highway 138 * WIS 140

Highway 140 * WIS 213

Highway 213

Railroads

Canadian Pacific The Canadian Pacific Railway () , also known simply as CPR or Canadian Pacific and formerly as CP Rail (1968–1996), is a Canadian Class I railway incorporated in 1881. The railway is owned by Canadian Pacific Kansas City, Canadian Pacific Ka ...

Union Pacific The Union Pacific Railroad is a Class I freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Pacific is the second largest railroad in the United States after BNSF, ...

Wisconsin and Southern Railroad The Wisconsin and Southern Railroad is a Class II regional railroad in Southern Wisconsin and Northeastern Illinois currently operated by Watco. It operates former Chicago, Milwaukee, St. Paul and Pacific Railroad (Milwaukee Road) and ...

Buses

* Beloit Transit * Janesville Transit System

Airport

Southern Wisconsin Regional Airport (KJVL) serves Rock County and the surrounding communities.

Adjacent counties

* Green County – west *

Dane County Dane County is a County (United States), county in the U.S. state of Wisconsin. As of the 2020 United States census, 2020 census, the population was 561,504, making it the second-most populous county in Wisconsin after Milwaukee County, Wiscon ...

– north * Jefferson County – northeast * Walworth County – east *

Boone County, Illinois Boone County is a county located in the U.S. state of Illinois. As of the 2020 census, the population was 53,448. Its county seat is Belvidere. Boone County is included in the Rockford, Illinois metropolitan area. History Unlike most of Ill ...

– south *

Winnebago County, Illinois Winnebago County is a county located in the U.S. state of Illinois. According to the 2020 census, it had a population of 285,350 making it the seventh most populous county in Illinois behind Cook County and its five surrounding collar countie ...

– south

Demographics

As of the census of 2020, the population was 163,687. The

population density Population density (in agriculture: Standing stock (disambiguation), standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geog ...

was . There were 70,068 housing units at an average density of . The racial makeup of the county was 81.3%

White White is the lightest color and is achromatic (having no chroma). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully (or almost fully) reflect and scatter all the visible wa ...

, 5.1%

Black Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without chroma, like white and grey. It is often used symbolically or figuratively to represent darkness.Eva Heller, ''P ...

African American African Americans, also known as Black Americans and formerly also called Afro-Americans, are an Race and ethnicity in the United States, American racial and ethnic group that consists of Americans who have total or partial ancestry from an ...

, 1.3% Asian, 0.5% Native American, 4.6% from other races, and 7.2% from two or more races. Ethnically, the population was 9.7%

Hispanic The term Hispanic () are people, Spanish culture, cultures, or countries related to Spain, the Spanish language, or broadly. In some contexts, Hispanic and Latino Americans, especially within the United States, "Hispanic" is used as an Ethnici ...

or Latino of any race. As of the

census A census (from Latin ''censere'', 'to assess') is the procedure of systematically acquiring, recording, and calculating population information about the members of a given Statistical population, population, usually displayed in the form of stati ...

of 2010, there were 160,331 people residing in the county. As of the

of 2000, were 152,307 people, 58,617 households, and 40,387 families residing in the county. The

was . there were 62,187 housing units at an average density of . The racial makeup of the county was 91.01%

white White is the lightest color and is achromatic (having no chroma). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully (or almost fully) reflect and scatter all the visible wa ...

, 4.63%

black Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without chroma, like white and grey. It is often used symbolically or figuratively to represent darkness.Eva Heller, ''P ...

, 0.28% Native American, 0.78% Asian, 0.04%

Pacific Islander Pacific Islanders, Pasifika, Pasefika, Pacificans, or rarely Pacificers are the peoples of the list of islands in the Pacific Ocean, Pacific Islands. As an ethnic group, ethnic/race (human categorization), racial term, it is used to describe th ...

, 1.77% from other races, and 1.50% from two or more races. 3.91% of the population were

or Latino of any race. 32.8% were of

German German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also Ge ...

, 13.0% Norwegian, 10.1% Irish, 7.5% English and 5.5% American ancestry. There were 58,617 households, out of which 33.60% had children under the age of 18 living with them, 53.50% were

married couples Marriage, also called matrimony or wedlock, is a culturally and often legally recognised union between people called spouses. It establishes rights and obligations between them, as well as between them and their children (if any), and b ...

living together, 10.90% had a female householder with no husband present, and 31.10% were non-families. 25.10% of all households were made up of individuals, and 9.70% had someone living alone who was 65 years of age or older. The average household size was 2.54 and the average family size was 3.03. In the county, the population was spread out, with 26.50% under the age of 18, 8.60% from 18 to 24, 29.80% from 25 to 44, 22.30% from 45 to 64, and 12.70% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 97.00 males. For every 100 females age 18 and over, there were 94.10 males.

Communities

Cities

* Beloit * Brodhead (mostly in Green County) * Edgerton (partly in

) *

Evansville Evansville is a city in Vanderburgh County, Indiana, United States, and its county seat. With a population of 118,414 at the 2020 census, it is Indiana's third-most populous city after Indianapolis and Fort Wayne, the most populous city in S ...

* Janesville (County seat) * Milton

Villages

* Clinton * Orfordville * Footville

Towns

* Avon * Beloit *

Bradford Bradford is a city status in the United Kingdom, city in West Yorkshire, England. It became a municipal borough in 1847, received a city charter in 1897 and, since the Local Government Act 1972, 1974 reform, the city status in the United Kingdo ...

* Center * Clinton * Fulton *

Harmony In music, harmony is the concept of combining different sounds in order to create new, distinct musical ideas. Theories of harmony seek to describe or explain the effects created by distinct pitches or tones coinciding with one another; harm ...

* Janesville * Johnstown * La Prairie *

Lima Lima ( ; ), founded in 1535 as the Ciudad de los Reyes (, Spanish for "City of Biblical Magi, Kings"), is the capital and largest city of Peru. It is located in the valleys of the Chillón River, Chillón, Rímac River, Rímac and Lurín Rive ...

Magnolia ''Magnolia'' is a large genus of about 210 to 340The number of species in the genus ''Magnolia'' depends on the taxonomic view that one takes up. Recent molecular and morphological research shows that former genera ''Talauma'', ''Dugandiodendr ...

* Milton * Newark *

Plymouth Plymouth ( ) is a port city status in the United Kingdom, city and unitary authority in Devon, South West England. It is located on Devon's south coast between the rivers River Plym, Plym and River Tamar, Tamar, about southwest of Exeter and ...

Porter Porter may refer to: Companies * Porter Airlines, Canadian airline based in Toronto * Porter Chemical Company, a defunct U.S. toy manufacturer of chemistry sets * Porter Motor Company, defunct U.S. car manufacturer * H.K. Porter, Inc., a locom ...

Rock Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wale ...

* Spring Valley *

Turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

* Union

Census-designated places

* Fulton *

Hanover Hanover ( ; ; ) is the capital and largest city of the States of Germany, German state of Lower Saxony. Its population of 535,932 (2021) makes it the List of cities in Germany by population, 13th-largest city in Germany as well as the fourth-l ...

* Shopiere

Unincorporated communities

* Afton * Anderson *

Avalon Avalon () is an island featured in the Arthurian legend. It first appeared in Geoffrey of Monmouth's 1136 ''Historia Regum Britanniae'' as a place of magic where King Arthur's sword Excalibur was made and later where Arthur was taken to recove ...

* Avon * Belcrest *

Bergen Bergen (, ) is a city and municipalities of Norway, municipality in Vestland county on the Western Norway, west coast of Norway. Bergen is the list of towns and cities in Norway, second-largest city in Norway after the capital Oslo. By May 20 ...

* Cainville * Center * Charlie Bluff * Cooksville * Coopers Shores * Crestview * Emerald Grove * Fairfield (partial) * Foxhollow * Indianford * Johnstown * Johnstown Center * Koshkonong (partial) *

Leyden Leiden ( ; ; in English and archaic Dutch also Leyden) is a city and municipality in the province of South Holland, Netherlands. The municipality of Leiden has a population of 127,046 (31 January 2023), but the city forms one densely connecte ...

* Lima Center *

* Mallwood * Maple Beach * Newark * Newville *

Porters Porters may refer to: * Porters, Virginia, an unincorporated community in Virginia, United States * Porters, Wisconsin, an unincorporated community in Wisconsin, United States * Porters Ski Area, a ski resort in New Zealand * Porters (TV series), '' ...

* Stebbinsville * Tiffany * Union * Victory Heights

Ghost towns/neighborhoods

* Fellows * Jefferson Prairie Settlement

Politics

Since 1988, Rock County has consistently voted for the Democratic candidate in every Presidential election. In 2024,

Kamala Harris Kamala Devi Harris ( ; born October 20, 1964) is an American politician and attorney who served as the 49th vice president of the United States from 2021 to 2025 under President Joe Biden. She is the first female, first African American, and ...

carried the county by the smallest margin of victory since

Michael Dukakis Michael Stanley Dukakis ( ; born November 3, 1933) is an American politician and lawyer who served as governor of Massachusetts from 1975 to 1979 and from 1983 to 1991. He is the longest-serving governor in Massachusetts history and only the s ...

in 1988.

Education

School districts include:
Text list
/ref> * Albany School District * Beloit School District * Beloit Turner School District * Brodhead School District * Clinton Community School District * Delavan-Darien School District * Edgerton School District * Evansville Community School District * Fort Atkinson School District * Janesville School District * Milton School District * Oregon School District * Parkview School District * Stoughton Area School District * Whitewater School District There is a state-operated school, Wisconsin School for the Blind and Visually Impaired.

References

External links

Rock County government website

Rock County map
from the Wisconsin Department of Transportation
Rock County 5.0

Rock County Historical Society

Beloit Janesville Symphony
{{authority control 1839 establishments in Wisconsin Territory Populated places established in 1839