Electromagnetic induction (EMI) was used to improve the quality of several high-intensity soil surveys in northern Illinois. At each site, apparent conductivity (ECa) data provided an additional layer of information, which improved knowledge of soils and directed further soil sampling. The information provided by ECa maps and supplementary soil sampling lead soil scientists to recognize additional soils or modify mapping concepts. Within the study sites, ECa maps facilitated the identification and delineation of some soil polygons and improved confidence levels. However, ECa maps lacked sufficient contrast to resolve similar soils and some soil polygons within these sites. While patterns of ECa influenced the judgments of soil scientists, ECa maps were not accepted as substitutes for high-intensity soil maps.