Lirceus usdagalun is a rare species of crustacean known by the common name Lee County cave isopod.

It is endemic to Virginia in the United States, where it is known from a single network of karst cave systems in Lee County.

[5] The species name, usdagalun, is from a Cherokee word meaning "cave" or "hole under rock".

[3] This organism is endemic to The Cedars, a cave region in the Powell River Valley of southwestern corner of Virginia.

When it was listed as an endangered species, only two populations were known, one of which was thought to have been extirpated by pollution from sawmill sawdust.