The piñon mouse is the largest member of the genus in Oregon. It is characterized by its enormous ears. Hair color varies geographically; overall, in central and eastern Oregon it is a pale-buff color with a wash of black on the dorsum, whereas mice from southwestern Oregon are bright ocherous on the shoulders and flanks and a dirty brown on the dorsum.

In Oregon, the piñon mouse has been found in Josephine, Jackson, Klamath, Lake, Deschutes, Jefferson, Grant, Crook, and Harney counties. East of the Cascade Range it is almost always associated with western juniper in rimrocks. In southwestern Oregon, it is associated with rocky outcrops vegetated by oaks.

Piñon mice are largely nocturnal.

Photo by Don Loarie, Flickr