Panthea virginarius, the Cascades Panthea, is a moth of the Noctuidae family. It is mainly found west and north of the Great Basin, from the coast of southern California northward to the Queen Charlotte Islands of British Columbia and the Alaskan Panhandle, eastward to central California, northern Nevada, Idaho, north-western Wyoming, western Montana, and south-western Alberta. A disjunct population is found in the Cypress Hills of Alberta and Saskatchewan. The larvae feed on Pseudotsuga menziesii and other conifers.