Campylopus introflexus (Hedw.) Brid. is a moss native to the southern hemisphere and well documented as an invasive species throughout Europe. The species was first collected in North America in 1967 in Del Norte Co., California, and now occurs primarily in coastal areas from Santa Barbara Co. to southern British Columbia. Herbarium specimens were assembled and verified to document the distribution of the species in western North America. Collection dates of specimens indicate a rapid invasion along the coast north and south from the first record, with a slower establishment of inland populations. The species is most prevalent in coastal, foggy areas. Many of the populations are associated with anthropogenic environments, but several populations appear to be invading relatively undisturbed sites. These are mostly characterized by poor soils along the coast, with the largest populations associated with Bishop Pine forests and stabilized sand dunes. A brief summary of ecological literature documenting the European invasion of C. introflexus suggests that the species, especially in the presence of disturbance, has the potential to negatively impact native bryophyte, lichen, and vascular plant species.