Sumas Mountain, in the Skagit Range of northwestern Washington northeast of Bellingham, stands just south of the Canada-United States border near a similarly named peak in British Columbia, linking both sides of the border within the Sumas River watershed. Known for high biodiversity and year-round hiking trails, it is largely public land owned by the Washington Department of Natural Resources, though some parcels are private. The area is open to recreation but managed mainly for timber harvest, leaving clearcuts and regrowing forest across many slopes. A low northern pass carries State Route 547 and formerly served the Chicago, Milwaukee, Saint Paul and Pacific Railroad, while the western slope includes the Swift Creek Landslide.