Rock River (Big Sioux River tributary)

Rock River
Mouth
Location
CountryUnited States
StateIowa, Minnesota
DistrictSioux County, Iowa, Lyon County, Iowa, Rock County, Minnesota, Pipestone County, Minnesota
Physical characteristics
Source 
  coordinates44°08′13″N 96°07′23″W / 44.1369°N 96.1231°W / 44.1369; -96.1231
MouthBig Sioux River
  coordinates
43°04′58″N 96°27′16″W / 43.0827°N 96.4545°W / 43.0827; -96.4545
  elevation
1,168 ft (356 m)
Discharge 
  locationRock Valley, Iowa
  average610 cu/ft. per sec.
Basin features
Tributaries 
  leftChampepadan Creek

The Rock River is a tributary of the Big Sioux River, about 144 miles (232 km) long, in southwestern Minnesota and northwestern Iowa in the United States. Via the Big Sioux and Missouri rivers, it is part of the watershed of the Mississippi River. The river's name comes from a prominent rocky outcrop about 175 feet high (designated "The Rock" on Joseph Nicollet's 1843 map of the area) of reddish-gray Sioux Quartzite, about 3 miles (5 km) north of Luverne. The outcrop of quartzite is contained in Minnesota's Blue Mounds State Park.