[2] All members of the genus are endemic to North America (Canada and the United States).

[4] The earliest known fossils of this genus are from the Hemphillian of Tennessee in the United States.

[1] Plethodon is part of the family Plethodontidae (lungless salamanders) and the subfamily Plethodontinae.

The genus Plethodon can be divided into two subgenera: the nominal subgenus Plethodon, which includes up to 49 eastern species (the bulk of diversity in the genus), and the subgenus Hightonia,[5] which includes 9 species native to the western part of North America.

[2] Most are native to eastern and central North America, with the Appalachian Mountains having the highest diversity.