Knife Lake and Santee Sioux are named after this river.
In turn Isanti County is named after the Santee Sioux.
The Knife River with its tributaries drains a 102-square-mile (260 km2) area of Mille Lacs and Kanabec counties.
After initially flowing southeastward for 19 miles (31 km) from Ernest Pool near Wahkon, it flows to Knife Lake, then continues to flow southeastward for another 5 miles (8 km) to the Snake River, just north of Mora.
At Mora, MN, the river has a mean annual discharge of 63 cubic feet per second.