Lyon County is located in the extreme northwestern corner of Iowa, bordering South Dakota on the west and South Dakota and Minnesota on the north. It lies entirely in the Missouri loess soil area and hence the soils in the county are chiefly loessial in character.
Brown, P. E.; O'Neal, A. M.; Gray, D. S.; and Meldrum, H. R., "Soil Survey of Iowa, Report No. 66—Lyon County Soils" (1932). Soil Survey Reports. 54.