Rock

Formed December 7, 1836 (17^th county)

Rock County (163,692), Janesville (65,615)

The 1955 Modern tan brick and concrete facility was enlarged in 1997.  The courthouse is at the intersection of Parker and Court streets.  United States Highway 14 Business is seven blocks to the south of the structure.  Carl Lloyd Ames is the architect.  There was an 1869 version previously.  The courthouse sits on a hill overlooking the Rock River.  The county was established on December 7, 1836 as the 17^th county.  Janesville has always been the county seat.  Rock County is named for the Rock River.  The county seat was named for ferry owner Henry F. Janes. 

Rock County government consists of a sheriff and 29 Supervisors.  Seven Circuit Court Judges and Ten Municipal Court Judges serve Rock County.  The county is on the southern border with Illinois.  Madison, Wisconsin is north and Rockford, Illinois is southwest of the county.  The county center is 3.8 miles South of Janesville.  The county is surrounded clockwise by Jefferson and Walworth counties and Illinois and Green and Dane counties. 

The area of the county is 718.1 square miles.  It is 41 out of 72 in the state.  It ranks 9 out of 72 in population in the state.  It has a density of 228.0 persons per square mile making it 13 out of 72 in the state.  Rock County has 75.8% of its population in its incorporated areas.  Interstate Highways 39/90 pass north to south in the county from Dane County to Illinois.  Interstate Highway 43 enters from Walworth County, east, and joins Interstate Highway 39 into Illinois.  United States Highway 14 comes from the east, Walworth County, and goes to the northwest, Dane County.  United States Highway 51 parallels Interstate Highway 39 from Dane County to Illinois.  The county is a rectangle.  Janesville is located near the center of the county.  Janesville is the county seat and the largest city.  It is 40.1% of the county population.  This county is in the Janesville Metropolitan Statistical Area.