Soils of the Caribou-Poker Creeks Research Watershed (41.5 sq mi), central Alaska, were mapped by standard soil conservation service (USDA) methods. Seven soil series were recognized. Bradway silt loams, Ester silt loams, Karshner silt loams and Saulich silt loams, all underlain by permafrost at shallow depth, make up 27% of the basin area. Olnes silt loams, Gilmore silt loams and Fairplay silt loams, covering 73% of the watershed area, are free from permafrost. Areal distribution of soils is depicted on a photo-mosaic base at scale 1:31,680. (Woodard-USGS).