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Rock River (Mississippi River tributary)

Coordinates: 41°28′57″N 90°36′58″W / 41.4825326°N 90.6162489°W / 41.4825326; -90.6162489 (Rock River mouth)
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Rock River
Rock River at Rockford, Illinois
Drainage basin of the Rock River
CountryUnited States
StatesWisconsin, Illinois
Physical characteristics
 • locationHoricon Marsh north of Horicon, Wisconsin
 • coordinates43°28′26″N 88°38′41″W / 43.4738889°N 88.6447222°W / 43.4738889; -88.6447222 (Rock River origin)
 • location
Confluence with the Mississippi River at Rock Island, Illinois
 • coordinates
41°28′57″N 90°36′58″W / 41.4825326°N 90.6162489°W / 41.4825326; -90.6162489 (Rock River mouth)
 • elevation
551 ft (168 m)
Length299 mi (481 km)
 • locationJoslin, Illinois
 • average7,195 cu/ft. per sec.[1]
Basin features
ProgressionRock River → MississippiGulf of Mexico
GNIS ID416824

The Rock River is a tributary of the Mississippi River, approximately 299 miles (481 km) long,[2][3] in the U.S. states of Wisconsin and Illinois. The river was known as the Sinnissippi to Sauk and Meskwaki peoples; the name means "rocky waters".[4]

The river, which has a notable higher western bank, begins with three separate branches that flow into the Horicon Marsh.[5] The northernmost branch, the West Branch, begins just to the west of the village of Brandon in Fond du Lac County, Wisconsin and flows east and then south to Horicon Marsh. The South Branch rises north of Fox Lake in Dodge County and flows east through Waupun to the marsh. The East Branch rises southeast of Allenton in Washington County just west of the Niagara Escarpment, and flows north and west through Theresa to the marsh.

Leaving the marsh, it meanders southward to the Illinois border, ending about 300 miles later at the Mississippi River at the Quad Cities in Illinois and Iowa. During its course it passes through Watertown, collects the Crawfish River in Jefferson, and receives the Bark River at Fort Atkinson. Shortly before merging, the Rock and Crawfish rivers cross Interstate 94. Both rivers flood the nearby land regularly, and lanes on I-94 were temporarily closed in 2008 because of this flooding.[6]

In northern Rock County, Wisconsin, it receives the Yahara River, and flows southward through tiny Fulton, Janesville and Beloit into northern Illinois, where it receives the Pecatonica River 5 miles (8 km) south of the state line. It flows south through Rockford, then southwest across northwestern Illinois, picking up the Kishwaukee River, passing Oregon, Dixon, Sterling (which has the Sinnissippi Mounds national historic site and local park) and Rock Falls before joining the Mississippi at Rock Island. It was on the Rock River in Dixon where Ronald Reagan was a lifeguard.[7] Reagan's favorite fishing spot, now called "Dutch Landing" after Reagan's nickname, was just southwest of Lowell Park on the Rock River.

There are 25 dams on the Rock River.[8] These are in Theresa (WI, 3 dams), Waupun (WI), Horicon (WI), Mayville (WI, 2 dams), Kekoskee (WI), Hustisford (WI), Watertown (WI, 2 dams), Jefferson (WI, 4 dams), Indianford (WI), Janesville (WI), Beloit (WI), Rockton (IL), Rockford Fordham (IL), Oregon (IL), Dixon (IL), Sterling / Rock Falls (IL, 2 dams), Milan (IL) and Rock Island (IL).[9]

The Rock River Trail in Dodge County, Wisconsin

The river is used for various water and paddling sports. The Rock River Water Trail is on the river from its headwaters above the Horicon National Wildlife Refuge in south central Wisconsin to the confluence with the Mississippi River at the Quad Cities of Illinois and Iowa 330 miles downriver. It crosses five counties in Wisconsin, six counties in Illinois and runs through 37 municipalities. The slow moving river passes scenic rural landscapes, wilderness areas and urban areas. The first two trailheads are at Waupun County Park in Waupun, Wisconsin and Rivers Edge Park in Theresa, Wisconsin and there are 32 additional access points in Dodge County, Wisconsin. The trail is part of the National Water Trails System and the first National Water Trail in Wisconsin and Illinois.[10]

Rock River Park is on County Road B about a half mile west of Johnson Creek, Wisconsin in Jefferson County, Wisconsin and offers river access and an artesian spring.[11]

Watertown River Walk 02

Cities and villages along the river[edit]

Rock River flooding downtown Fort Atkinson, June 2004
The frozen Rock River near Oregon, Illinois

Communities listed from north to south.

See also[edit]


  1. ^ "USGS Current Conditions for USGS 05446500 ROCK RIVER NEAR JOSLIN, IL". waterdata.usgs.gov.
  2. ^ U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map, accessed May 13, 2011
  3. ^ U.S. Geological Survey Geographic Names Information System: Rock River
  4. ^ "Castle Rock State Park". Illinois DNR. Archived from the original on 2007-04-01. Retrieved 2014-08-03.
  5. ^ "Upper Rock River basin | Wisconsin DNR". dnr.wisconsin.gov.
  6. ^ Channel 3000. "Interstate 94, Highway 151 Reopen As Water Recedes". Channel 3000. Archived from the original on 17 November 2009. Retrieved 3 February 2016.{{cite web}}: CS1 maint: numeric names: authors list (link)
  7. ^ City of Dixon. "Reagan's Roots".
  8. ^ "Dam Information". Rock River Trail. Retrieved 22 April 2014.
  9. ^ "Rock River Dams". PaddleAway. Retrieved 22 April 2014.
  10. ^ "Dodge County, Wisconsin : Rock River Water Trail". Retrieved 3 February 2016.
  11. ^ "Welcome to Jefferson County, Wisconsin". Retrieved 3 February 2016.

External links[edit]