Snoqualmia, new genus, is described for two species of polydesmid millipeds from the northwestern United States: Snoqualmia snoqualmie, new species, from Washington State, and S. idaho, new species, from Idaho. Males of S. idaho possess unusually complex gonopods, perhaps the most complex to be found in the Order Polydesmida. Snoqualmia is placed in context with other polydesmid genera known from North America. The polydesmid fauna of North America is discussed, as well as characters of the gonopods of the family.