Two squamulose species and one crustose species of Trapeliopsis are described from the western United States based on morphological, anatomical, and ITS sequence data. The newly described species pair, T. californica and T. steppica, consistently differs from T. wallrothii in morphology, ascospores, secondary products, and ITS sequence. Previous reports of Trapeliopsis wallrothii from North America should be referred to T. californica. Morphologically similar to Trapeliopsis californica, T. steppica is separated from that species by the presence of dark granular soredia in discrete roundish soralia; a thinner, duller cortex; and slightly smaller and more appressed squamules. Trapeliopsis steppica is apparently endemic to western North America, predominantly in the intermountain region. Trapeliopsis californica, an esorediate frequently fertile species, predominates in California and west of the Cascade crest in the Pacific Northwest. The third new species, T. bisorediata, is a rarely collected, but locally common in the semi-arid intermountain region of the Pacific Northwest. It is characterized by soredia of two types on a whitish pruinose crustose-areolate non-lobate thallus.