Three pedons within a 0.5-km2area (near the smelters) in the Copper Basin of Tennessee were located on upland, mid-slope, and toeslope landforms. Two pedons were located in some distant forests in areas unaffected by the smelting operations and accretion of sulfur. Morphological, physical, and chemical analyses were carried out on these soils. Mineralogical analyses were also made of sand, silt, and clay fractions by x-ray diffraction, thermal, petrographic, and chemical techniques. The clay and fine silt fractions contain interstratified mica/hydroxy-inter-layered vermiculite in the upper horizons. Kaolinite and gibbsite dominate subsoil horizons. The C horizon saprolite fine silt and clay fractions have kaolinite, vermiculite, and muscovite along with translocated or neoformed gibbsite. The sand fraction of A, B, and C horizons is composed mainly of quartz, muscovite, and kaolinite pseudomorphs of biotite. Albite and microcline feldspars occur in Cr horizon material and in the less weathered but oxidized underlying metagraywacke and quartz-mica schist.It is theorized that most of the kaolinite originated from feldspars and biotite while muscovite weathers to a muscovite-ver-miculite interstratified phase. Gibbsite, concentrated in the fine clay fraction, is neoformed, although some in the coarse clay and fine silt fractions may have transformed directly from feldspars in upper B horizons or from the increased desilication of kaolinite in the uppermost A and E horizons, a direct result of the acid-sulfate deposition from past open roasting and smelting of copper sulfide ores. Gibbsite in C horizons has been either neoformed or translocated as fine clay-sized particles from A and upper B horizons. No gibbsite was detected in Cr horizons or in the hard but oxidized rock beneath except as translocated coatings on crack and joint faces as opposed to large quantities of gibbsite in the Cr horizon of the pedon not affected by sulfur accretion. A definite relationship exists between landscape position and clay mineralogy. Permeable and freely drained upland and sideslope soils are dominated by gibbsite throughout, whereas lower sideslope and toeslope soils, which are either less permeable, have fluctuating water tables, or receive lateral surface and subsurface flow from higher areas, have less gibbsite, more kaolinite and vermiculite, higher base saturation, and other less weathered primary and secondary silicate minerals. Generally, there are no major soil mineralogical differences between soils affected and those not affected by sulfate, but there are obvious differences in pH and related chemical properties.