The majority of Admiralty is spruce-hemlock rainforest interspersed with small areas of muskeg. The timberline is typically 2000 to 2,500 feet. Above the timberline the forest gradually changes to alpine-tundra with rock outcrops and permanent to semi-permanent ice fields.
Much of the use of Admiralty Island takes place in the several major bays and inlets which penetrate deeply inland. They offer safe places to anchor and hike the adjacent beaches or estuaries while hunting, beach combing or photographing wildlife. Sitka black-tailed deer are numerous, especially during winter and spring, along these beach fringes. The largest inlet, Seymour Canal, contains some of the highest densities of nesting bald eagles anywhere in the world.
Other bays show evidence of past logging activity or have remnants of canneries, fox farms, and saltery sites from the fishery boom era.