Located in the South Central Region of Kansas, comprised of 15 counties and 12 minor river drainage basins or watersheds. While the majority stream flows are toward the SE, the Rattlesnake River flows to the NE, then turns SE in Rice County. The counties are: Edwards County, Kiowa County, Comanche County, Barber County, Pratt County, Stafford County, Barton County, Rice County, Reno County, Kingman County, Harper County, Sumner County, Sedgwick County, Harvey County and McPherson County.
The minor river drainage basins are: Rattlesnake, Upper & Lower Salt Forks of the Arkansas, Medicine Lodge, Main, N. & S. Forks Ninnescah, Gar/Peace, Cow, Little Arkansas, Middle Arkansas, Middle Arkansas/Slate, Chikaskia.
