Humboldt martens (Martes caurina humboldtensis), a subspecies of Pacific martens, occur in coastal Oregon and California and were designated as federally threatened and state Endangered (California). We assessed martens’ predicted distribution and interpret our findings as hypotheses correlated with the subspecies’ niche to inform strategic conservation actions. We spatially-thinned 10,229 locations collected 1996–2020 by applying a minimum distance of 500-m between locations, resulting in 384 locations. We independently optimized the spatial scale of each variable and used MaxEnt to create a predicted distribution. Humboldt marten locations were positively associated with increased shrub cover (Gautheria shallon), mast producing trees (e.g., Notholithocarpus densiflorus), increased pine (Pinus sp.) proportion of total basal area, and annual precipitation, areas with low and high amounts of canopy cover and slope, and cooler August temperatures. We found little evidence that Humboldt martens were associated with old-growth structural indices. This study provides an example of how limited information on lesser-known species can lead to differing interpretations, emphasizing the need for study-level replication in ecology. Conservation efforts and assessment of risks to Humboldt marten populations would benefit from continued survey effort to clarify distribution, population sizes, and fine-scale habitat use.