Deer Mountain (Alaska)  Deer Mountain is a mountain peak located in the Tongass National Forest in the Ketchikan Gateway Borough, Alaska, which dominates the skyline behind downtown Ketchikan. The Deer Mountain National Recreation Trail provides a strenuous hiking route to the summit, passing through temperate rainforests, muskeg and alpine meadows as it gains of elevation over from the trailhead in Ketchikan to the peak.