Rock River (Mississippi River tributary)

Rock River
Rock River at Rockford, Illinois
Drainage basin of the Rock River
Location
CountryUnited States
StatesWisconsin, Illinois
Physical characteristics
Source 
 • 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)
Mouth 
 • 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)
Discharge 
 • locationJoslin, Illinois
 • average7,195 cu/ft. per sec.
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, in the U.S. states of Wisconsin and Illinois. The river was known as the Sinnissippi to the Sauk and Meskwaki peoples; the name means "rocky waters".