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Where am ILOCATED

Rock County, Wisconsin

Rock County, Wisconsin, has 166,472 residents (July 2025 estimate). Its county seat is Janesville. It uses Central Time and covers 718 sq mi (1,860 km²) of land.

MilwaukeeMadisonGreen Bay
Rock County in Wisconsin
JanesvilleBeloitEdgertonEvansvilleMilton
Rock County and its neighbors (simplified outlines). Open in OpenStreetMap ↗
Resident population, July 2025
166,472
Land area
718 sq mi (1,860 km²)
County seat or government
Janesville
Time zone
Central TimeUTC-06:00 in January; UTC-05:00 in July
Median household income
$75,673 ± $2,128
Median home value
$231,600 ± $3,637
Median rent, with utilities
$1,037 ± $27
Homes lived in by their owners
71.2% ± 1.3 points
County type
County
Metro or micro area
Janesville-Beloit, WI metro areaCentral county
Water area
7.99 sq mi (20.7 km²)
State
Wisconsin
County code (FIPS)
55105
Coordinates (central point)
42.669880, -89.075284
Open this point in the location finder

These coordinates mark a central point for the area, not a street address. Income, home value, rent and homes lived in by their owners: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, ± margin at 90% confidence; checked on October 13, 2026.

Time zones in Rock County

Time zoneLocal time and UTC offsetNext clock change
Central TimeAmerica/ChicagoUTC-06:00 in January; UTC-05:00 in July. Enable JavaScript for the live clock.Enable JavaScript for upcoming changes.

Near a time-zone line, check where you are with the time-zone finder. Your phone’s setting can differ.

ZIP Code areas, largest first

  1. 5351148,701 people
  2. 5354629,867 people
  3. 5354524,703 people
  4. 5319020,499 people
  5. 5354819,916 people
  6. 5358919,550 people
  7. 5353818,813 people
  8. 5353412,241 people
  9. 5356311,280 people
  10. 535369,547 people
  11. 535206,687 people
  12. 535254,066 people
All 20
  1. 535213,640 people
  2. 535022,393 people
  3. 535852,264 people
  4. 535762,131 people
  5. 531141,979 people
  6. 53537752 people
  7. 53505358 people
  8. 53501165 people

20 ZIP Code areas overlap Rock County. People counts are 2020–2024 estimates for each whole ZIP area. Mailing ZIPs can differ; check an address with USPS ZIP Code Lookup.

Official county information

Rock County government website ↗ is the next stop for county offices, tax, voting, jury and records information. A geographic lookup cannot determine eligibility, tax liability or a court obligation.

Towns in Rock County, largest first

  1. Town of Beloit7,799 people
  2. Town of Janesville3,678 people
  3. Town of Fulton3,636 people
  4. Town of Milton3,103 people
  5. Town of Rock2,986 people
  6. Town of Turtle2,768 people
  7. Town of Harmony2,550 people
  8. Town of Union2,235 people
  9. Town of Newark1,377 people
  10. Town of Lima1,338 people
  11. Town of Center1,088 people
  12. Town of Clinton1,041 people
All 20
  1. Town of Porter961 people
  2. Town of Plymouth907 people
  3. Town of Bradford897 people
  4. Town of Magnolia864 people
  5. Town of La Prairie839 people
  6. Town of Johnstown638 people
  7. Town of Avon634 people
  8. Town of Spring Valley633 people

People counts are American Community Survey 2020–2024 5-year estimates. All towns in Wisconsin, by county

School districts in Rock County, largest first

  1. Janesville School District65,554 people
  2. Beloit School District36,714 people
  3. Oregon School District24,642 people
  4. Whitewater School District21,487 people
  5. Stoughton Area School District20,724 people
  6. Milton School District19,397 people
  7. Fort Atkinson School District18,426 people
  8. Delavan-Darien School District16,464 people
  9. Edgerton School District12,162 people
  10. Evansville Community School District10,186 people
  11. Beloit Turner School District8,881 people
  12. Brodhead School District6,391 people
All 15
  1. Clinton Community School District5,733 people
  2. Parkview School District5,411 people
  3. Albany School District2,946 people

Districts with land in the county; a district can cross county lines. People counts are American Community Survey 2020–2024 5-year estimates. A district boundary doesn’t decide which school a student attends.

Cities, towns and communities, largest first

These areas overlap the mapped boundary; an overlap does not mean that every address belongs to both.

  1. Janesville, Wisconsin (city)66,030 people
  2. Beloit, Wisconsin (city)36,534 people
  3. Edgerton, Wisconsin (city)6,014 people
  4. Evansville, Wisconsin (city)5,782 people
  5. Milton, Wisconsin (city)5,706 people
  6. Brodhead, Wisconsin (city)3,197 people
  7. Clinton, Wisconsin (village)2,041 people
  8. Orfordville, Wisconsin (village)1,473 people
  9. Footville, Wisconsin (village)908 people
  10. Hanover, Wisconsin (CDP)130 people
  11. Shopiere, Wisconsin (CDP)123 people
  12. Fulton, Wisconsin (CDP)31 people

Bordering areas, nearest first

Distances are straight lines between map points.

  1. Winnebago County, Illinois23 mi south
  2. Green County, Wisconsin27 mi west
  3. Walworth County, Wisconsin27 mi east
  4. Boone County, Illinois27 mi southeast
  5. Jefferson County, Wisconsin28 mi northeast
  6. Dane County, Wisconsin32 mi northwest

Before using this answer on a form

Use a precise point for address-level questions. A device accuracy circle can cross a boundary; confirm tax, voting or jury details with the responsible office.

Find the county where you are now, check its ZIP area, or check the time zone where you are.

See this county on Census.gov ↗

Areas that only touch the edge

These areas meet the boundary only along a sliver. Most addresses here are not in them; for an address near the line, check with the county.