Phuong, M. A., Lim, M. C., Wait, D. R., Rowe, K. C., & Moritz, C. (2014). Delimiting species in the genus Otospermophilus (Rodentia: Sciuridae), using genetics, ecology, and morphology. Biological Journal of the Linnean Society, 113(4), 1136-1151.
"Southern Washington; western Oregon; northern California to the north of the Sacramento–San Joaquin River Delta. Type locality: ‘bank Columbia River, Oregon'."