Monroe County is located in southern Iowa in the second tier of counties north of the Missouri state line and in the fourth tier west of the Mississippi River. It is entirely within the Southern Iowa loess soil area and the soils are, therefore, practically all of loessial origin. The only drift soils found are those derived from the old Kansan till which has been exposed through the erosion or washing away of the loessial covering.
Brown, P. E.; Orrben, C. L.; Meldrum, H. R.; and Englehorn, A. J., "Soil Survey of Iowa, Report No. 78—Monroe County Soils" (1936). Soil Survey Reports. 74.