The South Fork Crow River watershed covers 818,428 acres. It is located in south-central Minnesota and encompasses parts of Kandiyohi, Renville, Meeker, McLeod, Sibley, Wright, Carver, and Hennepin counties. The South Fork Crow River joins with the North Fork Crow at Rockford, and then joins the Mississippi River near Dayton. The majority of the watershed is within the Western Cornbelt Plains ecoregion, with a small portion extending into the North Central Hardwood Forest ecoregion. Major cities include Willmar, Hutchinson, Delano and Glencoe.
The South Fork Crow River watershed includes many lakes, streams, and wetlands. Buffalo Creek, a major tributary, flows into the South Fork Crow River downstream of Lester Prairie. Land use in the South Fork Crow River watershed is largely agricultural, with row crops and pasture/grass lands accounting for approximately 83% of the overall watershed acres.
Several lakes and parts of the South Fork Crow River do not meet water quality standards for beneficial uses such as aquatic recreation, drinking, and swimming. The main lake pollutant is phosphorus, causing algae blooms in summer months, and portions of the South Fork Crow and its tributaries are listed for pollutants such as bacteria, turbidity and low dissolved oxygen.