Faxonius is a genus of freshwater crayfish in the family Cambaridae.

[1] It includes the rusty crayfish, an invasive species in North America, and three species, F. virilis, F. immunis, and F. limosus, that are invasive to Europe.

This genus was formerly considered a subgenus of Orconectes.

Several former Orconectes species were added to this genus in 2017, leaving only the cave dwelling species unchanged, however F. stygocaneyi was reallocated,[2] even though it lives in caves.

These species belong to the genus Faxonius:[2]