The North American species of the genus Olophrum Erichson are revised. Seven species are recognized, the holarctic species O. latum Mäklin, O. boreale Gyllenhal, O. consimile Gyllenhal, and O. rotundicolle C. R. Sahlberg; the eastern North American species O. obtectum Erichson, and the new species O. cascadeuse known from northern California and eastern Oregon and O. idahoense known from southern Idaho.
Lectotypes are designated for O. marginatum Mäklin (= O. consimile), O. parvulum Mäklin (= O. consimile), O. convexum Mäklin (= O. rotundicolle), and O. convexicolle LeConte (= O. rotundicolle). The following new synonymy was established: O. bernhauerianum Scheerpeltz, O. recticolle Scheerpeltz, O. recticolle curtipenne Scheerpeltz are synonyms of O. consimile; O. quesneli Hatch is a synonym of O. boreale; and O. brevicolle Bernhauer is a synonym of O. latum. All species are described and illustrated with scanning electron photomicrographs and line drawings, five maps showing the North American distribution of each species are provided, and a key is presented to aid in the identification of the species. All available records and biological data for the species are provided.