The cause of extinction of the noble marten (Martes americana nobilis), as well as its taxonomic position, has been the subject of debate in recent years. This extinct marten, a close relative of the extant American marten (Martes americana), is known from 18 sites in western North America, most dating to the late Pleistocene. Because boreal fauna were associated with the late-Pleistocene noble marten, researchers generally believed that it inhabited boreal forests like the American marten, and competition between the 2 may have caused its extinction. Recent discoveries of noble martens associated with xeric fauna from Holocene contexts have called these assumptions into question. I explore the adaptation and habitat of the noble marten with an analysis of its faunal associations and find-site locations. The analysis suggests that the noble marten was adapted to open, mesic grasslands in montane foothills, and was likely not sympatric with the American marten. I also introduce a new Holocene noble marten specimen, a right mandible dating to 6,400 years ago, from Mummy Cave, an archaeological site in northwestern Wyoming.