Peromyscus keeni occurs along the coast from southeastern Alaska through western British Columbia to western Washington. It is recorded in forests and young growth; on small islands, beach logs and rocks provide shelter.
Its back is brown and its underside is light gray. The tail is dark above and light below, and the ears are large and hairless.
It occurs in forest and young-growth habitat and searches for fruit and seeds on the ground. On small islands, beach logs, rocks, and other debris are reported as cover.
An extinction-risk assessment has not been added yet.