On May 25th, 2014, a 54.5 Mm3 rock avalanche occurred in the West Salt Creek valley in western Colorado following heavy rainfall on top of snow (Coe and others, 2016a). The data in this project includes boulder density in 20-m x 20-m grid cells for the entire West Salt Creek rock avalanche deposit. The grid cells cover 2,154,800 m2, which accounts for nearly the entire surface of the deposit. We estimated boulder density by counting 1-m or larger diameter boulders of sedimentary rock that are visible in high-resolution Unmanned Aircraft System (UAS) imagery collected for the area in July of 2014 (Coe and others, 2016b). Basalt boulders were excluded from the count because field observations indicated that they generally stayed intact as the avalanche moved downslope, whereas the sedimentary boulders showed evidence of fragmentation during downslope movement. Variable clarity, contrast and resolution of the imagery precluded mapping smaller boulders. Experimentation with 5-m, 10-m and 20-m resolution grids showed that 20-m resolution was fine enough to show the spatial pattern of boulder density across the deposit and coarse enough to show statistically meaningful variation in boulder density. The attribute table contains fields containing (1) the boulder count in each grid cell, as well as (2) six categories of successively increasing boulder density. Lewis and others (2022) describe the mapping procedures in greater detail. References cited Lewis, A.C., Baum, R.L., and Coe, J.A., in review, Distribution of large boulders on the deposit of the West Salt Creek rock avalanche, western Colorado: U.S. Geological Survey Data Report 22-XXXX. Coe, J.A., Baum, R.L., Allstadt, K.E., Kochevar, B.F., Jr., Schmitt, R.G., Morgan, M.L., White, J.L., Stratton, B.T., Hayashi, T.A., and Kean, J.W., 2016a, Rock-avalanche dynamics revealed by large-scale field mapping and seismic signals at a highly mobile avalanche in the West Salt Creek valley, western Colorado: Geosphere, v. 12, no. 2, p. 607–631, https://doi.org/10.1130/GES01265.1. Coe, J.A., Baum, R.L., Allstadt, K.E., Kochevar, B.F., Schmitt, R.G., Morgan, M.L., White, J.L., Stratton, B.T., Hayashi, T.A., and Kean, J.W., 2016b, Map data and unmanned aircraft system imagery from the May 25, 2014 West Salt Creek rock avalanche in western Colorado: U.S. Geological Survey data release, http://dx.doi.org/10.5066/F74J0C55.