The Cedar River is a river, in Iowa, which is named after the juniper trees growing there (mistakenly called "cedar" by early settlers). According to the Black Hawk County Green Party, it has the highest nitrate levels of any river in the world. The surrounding region is known officially as the Cedar River Valley, however it is more commonly referred to simply as Cedar Valley.

The headwaters of the Cedar River are located in Dodge County, Minnesota, consisting of a west fork and middle fork approximately three miles northeast of the town of Blooming Prairie, and an east fork approximately one mile south of the town of Hayfield. The endpoint of the Cedar River is located in Louisa County, Iowa at the town of Columbus Junction, where it joins with the Iowa River. The total length is approximately 300mi, or 483km.

Major cities (with populations greater than 20,000) located along the Cedar River include Austin, Minnesota, Cedar Falls, Iowa, Waterloo, Iowa, and Cedar Rapids, Iowa.

The Cedar River is also sometimes referred to as the Red Cedar River.

See also

• List of Iowa rivers
• List of Minnesota rivers