Soil-geomorphic investigations were undertaken as part of a geoarchaeological assessment of the Tomato Springs site (CA-ORA-244), which is located at the western edge of the foothills of the Santa Ana Mountains in southern California. Most of the site is situated on the slopes and summits of two prominent ridges sandwiched between Bee and Round canyons, with soils mapped predominantly as the San Andreas (Typic Haploxerolls) and Cieneba (Typic Xerorthents) series. This geoarchaeological assessment was aimed at: (1) documenting the soil stratigraphy in different parts of the site; (2) assessing the degree of stratigraphic integrity on terraced hillslopes and eroded ridges; and (3) evaluating artifact densities and distributions in relation to the different landscape positions and soils. The slope classification of L. C. King (1957) provides a simple but useful conceptual model for explaining artifact densities and distributions across the flat to moderately steep terrain of the site. Soil and topographic variability associated with different slope elements (e.g., summits, shoulder slope, backslope, footslope, and toeslopes) and geomorphic processes (e.g., erosion, transportation, deposition, and soil formation) provided information that could explain the formation, alteration, and preservation of the archaeological record. Variations among cultural deposits and geomorphic settings were used to assess how humans used and adapted to different landscape positions of the Tomato Springs site. The intensity of human land-use, as measured by artifact types and distributions, varied dramatically, with artifacts concentrated in the A horizons of summits and footslopes. The greatest geomorphic stability and thickest cultural deposits were documented on footslopes where argillic horizons had formed. Artifacts were also concentrated as lag deposits on shoulder slopes where sheetwash erosion had removed all or most of the A horizon.