Butler County is located in northeastern Iowa in the third tier of counties south of the Minnesota state line and in the fourth tier of counties west of the Mississippi River. It is mainly in the Iowan drift soil area, and hence most of the soils are of drift origin. There is a small acreage of loess soils undoubtedly derived from the Mississippi loess deposit.
Brown, P. E.; Elwell, J. A.; Meldrum, H. R.; and Bennett, R. E., "Soil Survey of Iowa, Report No. 70—Butler County Soils" (1933). Soil Survey Reports. 82.