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part ofTongass National Forest, US Forest Service
Status: Open year round.   Season Dates


Castle Flats Cabin is located on Kupreanof Island on the coastal waters of southeastern Alaska. It offers access to a variety of outdoor recreational opportunities, as well as a secluded place to enjoy its beautiful surroundings.

The cabin is accessible only by boat or float plane from Petersburg, and tides impact access. During low tides, a 2-mile hike is necessary to reach the cabin. Visitors are responsible for their own travel arrangements and safety, and must bring several of their own amenities.

Natural Features:

The cabin is located on southeastern Kupreanof Island, on the edge of the Castle River tide flat in Duncan Canal. The surrounding terrain is predominantly flat, old-growth forest and muskeg.

A variety of wildlife makes its home in the area, including moose, deer, black bears, waterfowl and grouse. During spring migration, the flats are host to many bird species.


The Castle River Trail is an easy, 1-mile trail that leads first to the Castle River Cabin and continues upstream another half-mile through forest and muskeg. Wildlife can be seen along the trail. Waterfowl, grouse, moose, deer and bear hunting is available in designated seasons as per state or federal hunting regulations; click here for more information from the Alaska Department of Fish and Game.

Visitors also enjoy fishing for steelhead from April to May, trout from May to October, and coho salmon in mid-August through mid-September.

A small rowboat and oars are provided at the cabin. Life jackets are not provided and visitors must bring their own. Visitors may also choose to bring a small, outboard motor. Crossing the tide flats by boat requires at least a 13-foot tide (local tide tables).


The hunter-style cabin has four wooden bunks and can accommodate up to five people. It is equipped with a table and benches, wood stove and oil heater.

The cabin has a covered porch and an outhouse with a pit toilet. Firewood is generally provided, but is not guaranteed. A broom, dust pan, axe and splitting maul are generally available, but may be missing or damaged.

Drinking water is not available. The nearest water source is a small stream west of the cabin, but water must be treated or boiled prior to consumption. Visitors may want to bring their own drinking water to avoid the hassle.

Heating oil is not provided. Visitors need to bring No. 1 heating oil for the clean-burning oil heater, in addition to sleeping bags and pads, a cook stove and cooking gear, towels, food, clothing and garbage bags, among other necessities. All trash and food must be packed out, and visitors are expected to clean the cabin before leaving.

Click here for more cabin details and maps.

Activities and Amenities

Within Facility
  • Axe
  • Birding
  • Boating
  • Broom & Dust Pan
  • Bunkbed(s)
  • Cabin Rentals
  • Firewood
  • Fishing
  • Heater
  • Hiking
  • Hunting
  • Non-Motorized Boating
  • Pit Toilets
  • River Access
  • Table & Chairs
  • Trails
  • Wildlife Viewing
  • Wood Stove
Know Before You Go
  • This facility is located in an extremely remote and wild area; before making a reservation, become aware of bear, water, and weather safety (including cold)
  • Recreating in Alaska can present both obvious and hidden dangers; please be aware of your surroundings and be prepared for extended stays due to occasionally poor weather
  • Tides affect access to this cabin; consult local tide tables before making a reservation
  • Water taken from the stream should be treated or boiled prior to consumption
  • Firewood at the cabin is supplied only for heating the cabin, it is not for outdoor campfires; collect dead and down wood from the forest for your outdoor campfire
  • Use of this cabin by a commercial operator, such as an outfitter or guide, is not allowed
  • High levels of Paralytic Shellfish Poisoning (PSP) have been recorded in this area
  • All garbage and food must be packed out
  • Please report missing or damaged items to the Petersburg Ranger District
  • Learn more about Tongass National Forest
  • Don't Move Firewood: Prevent the spread of tree-killing pests by purchasing firewood near your destination and burning it on-site. For more information visit dontmovefirewood.org.

Getting There:

GPS Info. (Latitude, Longitude):
56.64611, -133.25
56°38'46"N, 133°15'0"W

From Petersburg, it is 16 miles by float plane or 30 miles by boat. A 15-foot tide is required for float plane access, and a 13-foot tide is required for boat access. At lower tides, there is up to a 2-mile hike along the tide flat to the cabin.

Castle Flats Cabin can be found on USGS topographic map Petersburg C-4. Maps are available online or by calling the Petersburg Ranger District at (907) 772-3871.

Contact Information:

Mailing Address:

PO BOX 1328

Phone Number:

Information:  (907)772-3871
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