Wapello county is located in southeastern 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 Mississippi loess soil area and practically all of its soils are loessial in origin.
Stevenson, W. H. and Brown, P. E., "Soil Survey of Iowa, Report No. 18—Wapello County" (1921). Soil Survey Reports. 16.