These data are from samples gathered in 2016 from the CLY-2 site in eastern Washington, USA (Location: 46.3131, -118.4874, WGS84). The CLY-2 is a roadcut exposing a vertical face of the Palouse loess containing carbonate paleosol horizons and tephras. The samples were collected from a set of three stepped trenches into the roadcut about 10-20 m apart. Each trench was excavated to a depth of about a meter to expose a fresh surface; the final ~10 cm was excavated with non-ferrous digging tools. One sample from each depth was analyzed for particle size distribution using a MasterSizer 3000 laser diffraction particle size analyzer with a Hydro LV wet sample dispersion unit; these data are reported as both particle size quantiles (e.g. D50 is the diameter than is greater than 50% of the particles) and Wentworth particle size classes.