A new family of oribatid mites, Dendroeremaeidae, is described on the basis of material collected from bark and twigs of coniferous and deciduous trees in northwestern North America. Dendroeremaeus n. gen. is described as the type genus of the family, with Dendroeremaeus krantzi n. sp as type species. A second species, Dendroeremaeus foveolatus n. sp. is described also. The characteristics and relationships of this family to others of the poronotic Brachypylina are discussed, and the family is included in the early derivative poronotic taxon Licneremaeoidea, and may be most closely related to Lamellareidae or Passalozetidae. Adults of Dendroeremaeus krantzi and D. foveolatus have the octotaxic system developed on the notogaster, and nymphs are unideficient and plicate. Scalps are retained by some tritonymphs.