In 2008, soil samples were collected at 139 sites throughout the Wyoming Landscape Conservation Initiative study area in southwest Wyoming. These samples, representing a density of 1 site per 440 square kilometers, were collected from a depth of 0-5 cm and analyzed for a suite of more than 40 major and trace elements following a near-total multi-acid extraction. In addition, soil pH, electrical conductivity, total nitrogen, total and organic carbon, and sodium adsorption ratio were determined. The resulting data set provides a baseline for detecting changes in soil composition that might result from natural processes or anthropogenic activities. This report describes the sampling and analytical protocols used, and makes available all the soil geochemical data generated in the study.