These first North American records for Polymerus cognatus (Fieber) from across Canada and the northeast United States, and P. vulneratus (Wolff) from northwest North America, indicate that the two species are naturally Holarctic. Diagnoses and dorsal habitus illustrations are provided to distinguish the taxa from other North American Polymerus species. An argument for considering P. balli Knight, P. cognatus, P. elegans (Reuter), P. flaviloris Knight, P. froeschneri Knight, and P. vulneratus a monophyletic species-group is presented.