We evaluated multiscale habitat selection by threatened Newfoundland (Canada) martens (Martes americana atrata) across landscapes composed of a range of habitat types to test the hypothesis that martens preferred mature (61–80-yr-old) and overmature (>80 yr) conifer stands. At both the landscape and stand scales, adult (≥1 yr) resident martens (n  =  58, 92 yr-specific home ranges) selected for, or used in proportion to availability, a broad range of habitat types, including recent cuts ≤5 yr old, regenerating forest <6.5 m, precommercially thinned stands, and mature and overmature forest. Marten home ranges were not dominated by mature and overmature forest; median availability of mature and overmature forest within individual home ranges was only 30% (range  =  11–76%). Age distributions were not different among martens with high, intermediate, and low quantity of mature and overmature forest in their home range; our data do not indicate that martens inhabiting ranges with little mature and overmature forest were compromising fitness. Habitat selection by martens in Newfoundland was more generalized than has traditionally been inferred, and we suggest that inherent landscape fragmentation, in combination with absence of many predators and competitors (i.e., ecological release), caused the Newfoundland marten to evolve to use a more generalized habitat niche than many mainland populations of American martens. We recommend that landscapes suitable for marten not exceed >29% younger aged forest. Maintaining resident martens in landscapes where forest harvesting is occurring requires prescriptions that recognize the highly fragmented nature of the natural landscape, the prevalence of mature and overmature forest, younger forests, avoided land-cover types, and human access.