The Ninnescah River, a 56.4-mile stream of southern Kansas, is composed of two branches. The north fork rises in the southern part of Stafford County and flows northeastwardly to Plevna in Reno County, where the course changes to the southeast. The south fork has its source in the western part of Pratt County. Its course is almost due east through Pratt and Kingman Counties until it unites with the north fork in the southwest corner of Sedgwick County. The main stream then flows southeast and empties its waters into the Arkansas River near Oxford, Kansas.