We present a collections-based checklist for bryophyte and lichen species known or expected to occur within the boundaries of Malheur National Forest, an administrative unit spanning several climatic zones and vegetation types in the semi-arid Blue Mountains of eastern Oregon. A synthesis of survey, literature and herbarium records yielded 2 hornwort species, 51 liverworts, 219 mosses and 276 lichens. Notable bryophytes included: Anoectangium aestivum, Bruchia bolanderi, Bryum calobryoides, Calliergonella lindbergii, Racomitrium depressum, Fontinalis hypnoides, Preissia quadrata and Schistidium cinclidodonteum. Notable lichens included: Lecanora pringlei, Peccania arizonica, Placidiopsis cinerascens, Schaereria dolodes and 6 calicioid lichens. We also provide conservation notes and conclude with a brief synopsis of collecting history in the region.