The Humboldt marten (Martes caurina humboldtensis) is a federally threatened and state endangered subspecies of the Pacific marten (Martes caurina). Humboldt martens occur in four contemporary populations, designated “Extant Population Areas” by the United States Fish and Wildlife Service, in coastal Oregon and northern California, each presumed to be at risk of extinction due to their small size and isolation. Despite efforts to better understand their contemporary distribution and habitat associations, little is known about the abundance and interspecific relationships of Humboldt martens across their current range. To fill these information gaps, we deployed 288 non-invasive hair snares and 132 remote cameras across three sampling grids in the North Coastal California Extant Population Area from August to November 2022. We will incorporate remote camera detections into single season occupancy models to estimate space-use of martens and co-occurring carnivores. Further, we will incorporate genotyped marten hair samples into spatial capture-recapture models to estimate abundance and density of Humboldt martens relative to co-occurring carnivores and habitat structure. These findings will bolster our understanding of Humboldt marten density across a broad range of habitat types, as well as how co-occurring carnivores may influence marten ecology.