Oregonia is a genus of crabs, comprising two extant species[1] and one fossil species:[2] It is classified in the family Oregoniidae under the spider crab superfamily Majoidea.

[1] The members of the genus are characterized by subtriangular or suboblong carapaces moderately covered with small protrusions (tubercles).

The palms (manus) of the claws are long, compressed, and widen on the outer ends.

The walking legs (pereiopods) are slender and decrease in length regularly towards the back.

[4][7] O. hirta in particular was misidentified as a separate species due to the sexual dimorphism exhibited by majoid crabs.