The Shell Rock River is a 113 miles (181.9 km) tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Cedar River in southern Minnesota

Minnesota

Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...

 and northern Iowa

Iowa

Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...

 in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. Via the Cedar and Iowa

Iowa River

The Iowa River is a tributary of the Mississippi River in the state of Iowa in the United States. It is about long and is open to small river craft to Iowa City, about from its mouth...

 rivers, it is part of the watershed

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 of the Mississippi River

Mississippi River

The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...

. The United States Board on Geographic Names

United States Board on Geographic Names

The United States Board on Geographic Names is a United States federal body whose purpose is to establish and maintain uniform usage of geographic names throughout the U.S. government.-Overview:...

 settled on "Shell Rock River" as the stream's name in 1931. According to the Geographic Names Information System

Geographic Names Information System

The Geographic Names Information System is a database that contains name and locative information about more than two million physical and cultural features located throughout the United States of America and its territories. It is a type of gazetteer...

, it has also been known by the spelling "Shellrock River".

Course

The Shell Rock River flows from Albert Lea Lake in Freeborn County, Minnesota

Freeborn County, Minnesota

As of the census of 2000, there were 32,584 people, 13,356 households, and 9,015 families residing in the county. The population density was 46 people per square mile . There were 13,996 housing units at an average density of 20 per square mile...

, and soon enters Iowa, flowing generally south-southeastwardly through eastern Worth

Worth County, Iowa

-2010 census:The 2010 census recorded a population of 7,598 in the county, with a population density of . There were 3,548 housing units, of which 3,172 were occupied.-2000 census:...

, northeastern Cerro Gordo

Cerro Gordo County, Iowa

-2010 census:The 2010 census recorded a population of 44,151 in the county, with a population density of . There were 22,163 housing units, of which 19,350 were occupied.-2000 census:...

, western Floyd

Floyd County, Iowa

-2010 census:The 2010 census recorded a population of 16,303 in the county, with a population density of . There were 7,526 housing units, of which 6,886 were occupied.-2000 census:...

, northeastern Butler

Butler County, Iowa

-2010 census:The 2010 census recorded a population of 14,867 in the county, with a population density of . There were 6,682 housing units, of which 6,120 were occupied.-2000 census:...

, southwestern Bremer and northwestern Black Hawk

Black Hawk County, Iowa

-2010 census:The 2010 census recorded a population of 131,090 in the county, with a population density of . There were 55,887 housing units, of which 52,470 were occupied.-2000 census:...

 counties, past the town of Glenville

Glenville, Minnesota

Glenville is a city in Freeborn County, Minnesota, United States, along the Shell Rock River. The population was 643 at the 2010 census.-Geography:...

 in Minnesota and the towns of Northwood

Northwood, Iowa

Northwood is a city in Worth County, Iowa, United States, along the Shell Rock River. The population was 2,050 at the 2000 census. It is the county seat of Worth County.Northwood is part of the Mason City Micropolitan Statistical Area.-Geography:...

, Plymouth

Plymouth, Iowa

Plymouth is a city in Cerro Gordo County, Iowa, United States, along the Shell Rock River. The population was 429 at the 2000 census. It is part of the Mason City Micropolitan Statistical Area.-Geography:Plymouth is located at ....

, Rock Falls

Rock Falls, Iowa

Rock Falls is a city in Cerro Gordo County, Iowa, United States, along the Shell Rock River. The population was 170 at the 2000 census. It is part of the Mason City Micropolitan Statistical Area.-Geography:Rock Falls is located at ....

, Nora Springs

Nora Springs, Iowa

Nora Springs is a city in Cerro Gordo and Floyd Counties in the U.S. state of Iowa, along the Shell Rock River. As of the 2000 census, the city population was 1,532....

, Rockford

Rockford, Iowa

Rockford is a city in Floyd County, Iowa, United States, at the confluence of the Shell Rock and Winnebago Rivers. The population was 907 at the 2000 census.-Geography:Rockford's longitude and latitude coordinatesin decimal form are 43.052833, -92.949203...

, Marble Rock

Marble Rock, Iowa

Marble Rock is a city in Floyd County, Iowa, United States, along the Shell Rock River. The population was 326 at the 2000 census.-Geography:Marble Rock is located at ....

, Greene

Greene, Iowa

Greene is a city in Butler County, Iowa, along the Shell Rock River, and along Butler County's northern border, where Butler and Floyd counties meet. The population was 1,099 at the 2000 census...

, Clarksville

Clarksville, Iowa

Clarksville is a city in Butler County, Iowa, United States, along the Shell Rock River. The population was 1,441 at the 2000 census.-Geography:Clarksville is located at 42°46'58" North, 92°40'11" West ....

 and Shell Rock

Shell Rock, Iowa

Shell Rock is a city in Butler County, Iowa, United States, along the Shell Rock River. The population was 1,298 at the 2000 census. The city is located along the county's eastern border, between Butler and Bremer counties.-Geography:...

 in Iowa. It joins the West Fork of the Cedar River in Black Hawk County, about 6 miles (10 km) north-northwest of Cedar Falls

Cedar Falls, Iowa

Cedar Falls is a city in Black Hawk County, Iowa, United States, and it is home to one of Iowa's three public universities, the University of Northern Iowa. The population was 39,260 in the 2010 census, an increase from the 36,145 population in the 2000 census...

. At Rockford, Iowa, it collects the Winnebago River

Winnebago River

The Winnebago River is a river in northern Iowa. It is a tributary of the Shell Rock River, part of the Cedar River watershed that flows via the Iowa River to the Mississippi River. The Winnebago River rises in Winnebago County, Iowa north of Leland and flows south through Forest City, then east...

from the west.