Aims of the distributional study here reported on concerning the fishes of a part of the Arkansas River Basin of south-central Kansas were as follows:

1. Ascertain what species occur in streams of the three counties.
2. Ascertain habitat preferences for the species found.
3. Distinguish faunal associations existing in different parts of the same stream.
4. Describe differences and similarities among the fish faunas of the several streams in the area.
5. Relate the findings to the over-all picture of east-west distribution of fishes in Kansas.
6. List any demonstrable effects of intermittency of streams on fish distribution within the area.

Cowley and Chautauqua counties form part of the southern border of Kansas, and Elk County lies directly north of Chautauqua. The following report concerns data only from those three counties unless otherwise noted. They make up an area of 2,430 square miles having a population of 50,960 persons in 1950 (55,552 in 1940, and 60,375 in 1930). The most populous portion of the area is western Cowley County where Arkansas City with 12,903 inhabitants and Winfield with 10,264 inhabitants are located. Each of the other towns has less than 2,000 inhabitants. In the Flint Hills, which cross the central portion of the area surveyed, population is sparse and chiefly in the valleys.

Topographically, the area is divisible into three general sections: the extensive Wellington formation and the floodplain of the Arkansas River in western Cowley County; the Flint Hills in the central part of the area; and the “Chautauqua Hills” in the eastern part.