Six new aleocharine species are described and illustrated from the Yukon and Alaska: Atheta (Dimetrota) cadeti Klimaszewski and Godin, sp. nov.; Atheta (Hypatheta) pseudomet lakatlana Klimaszewski and Godin, sp. nov.; Cypha inexpectata Klimaszewski and Godin, sp. nov.; Oxypoda yukonensis Klimaszewski and Godin, sp. nov., Oxypoda pseudoconvergens Klimaszewski and Godin, sp. nov.; and Clusiota antennalis Klimaszewski and Godin, sp. nov.Atheta (Rhagocneme) subsinuata (Erichson), known from the western Palaearctic region, was discovered in the Yukon and is reported in North America for the first time as an adventive species. Amischa tersa Casey is recorded from Canada and the Yukon for the first time. Twenty-four new records of aleocharine species from the Yukon are provided in addition to species described as new to science. One hundred and fifteen digital images of external and genital structures are provided for species identification.