Openings · last 7 days
2
Booking reality
Campsite Sniper detected 2 site openings here in the last 7 days
01 · Detected Opening History · the openings record · file CS-233002
When Castle Flats Cabin reopens
Castle Flats Cabin's openings record: every site-date Campsite Sniper detected turning available, logged and time-stamped. Refreshed hourly.
Openings · last 30 days
2
Openings · last 90 days
7
Only 7 openings in the last 90 days: not enough recent activity for a reliable pattern. A free Campsite Sniper alert watches around the clock instead, and pings you the moment one opens.
02 · Availability Outlook · Sep 18, 2026 – Mar 19, 2027 · of 1 monitored site
Of the 183 tracked site-nights (Sep 18, 2026 – Mar 19, 2027): 155 open for online reservation · 28 reserved.
Where the open windows are
15.3% of tracked site-nights are not currently open for online reservation. 155 of 183 remain open; here is where they are.
Load status
Sep 18, 2026 – Mar 19, 2027Not open online15.3%
Open site-nights155 / 183
Reserved (of online inventory)28 / 183
Weekday openings88
Weekend openings67
Of the open cabin-nights on mapped sites, 88 fall on weekdays and 67 on weekends (Fri–Sun).
Open dates by month
Sep 2026 – Mar 2027December holds the most room. 31 of 31 site-nights are still open there.
Holiday windows
Sites open per night · of 1 cabin| Window | Night | Sites open | Status |
|---|---|---|---|
| Labor Day | SAT Sep 5 | 0 | None open |
| SUN Sep 6 | 0 | None open | |
| MON Sep 7 | 0 | None open | |
| Thanksgiving | THU Nov 26 | 0 | None open |
| FRI Nov 27 | 0 | None open | |
| SAT Nov 28 | 0 | None open | |
| Christmas | THU Dec 24 | 1 | Open |
| FRI Dec 25 | 1 | Open | |
| New Year | THU Dec 31 | 1 | Open |
| FRI Jan 1 | 1 | Open |
Labor Day: no online availability on any tracked night. Thanksgiving: no online availability on any tracked night. Christmas: 1 cabin is available for the complete two-night stay. New Year: 1 cabin is available for the complete two-night stay.
Availability
Most open cabin-nights · tracked window| Cabin | Open cabin-nights |
|---|---|
| P10 | 155 |
This cabin currently has 155 cabin-nights available.
Next windows
As of Sep 18, 2026 snapshotNext open dateFri · Sep 18
Next open weekendFri · Sep 18
The next bookable night is Sep 18; the first open weekend starts Sep 18. Campsite Sniper can watch later dates for you.
Stays and site detail
155 open cabin-nights across 1 cabin at Castle Flats Cabin, from the same hourly snapshot as everything above.
Multi-night stays. 4 2-night, 3 3-night, 2 7-night openings where a single site is free for every night, per Campsite Sniper's current snapshot — soonest Sep 18 at site P10.
All 1 cabin with current availability
| Cabin | Max RV | Hookups | Open cabin-nights | Longest run | Dates |
|---|---|---|---|---|---|
| P10 | Not recorded | None | 155 | 111 nights | Sep 18, Sep 19, Sep 20, Sep 21, Sep 22, Sep 23, Sep 24, Sep 25, Sep 26, Sep 27, Sep 28, Sep 29 +143 more |
About Castle Flats Cabin
Overview
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.
Recreation
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).
Facilities
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.
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.
1 monitored cabinNo hookups1 shadedMax party 5
Getting there
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.
Po Box 1328, Petersburg, AK 99833907-772-3871
BoatingCampingFishingHikingHuntingWildlife Viewing
View on Recreation.gov ↗ Get directions ↗
03 · Field Photos · roll CS-233002 · facility + sites
Photo gallery
Roll CS-233002 · Castle Flats Cabin · Petersburg AK9 frames · facility + sites
FAQ
How do I get a reservation at Castle Flats Cabin?
Reservations for Castle Flats Cabin are made through Recreation.gov. The current snapshot shows substantial availability: 155 of 183 tracked site-nights are open (84.7%), though availability can change. Campsite Sniper has also detected 7 site openings here in the last 90 days, so further dates may appear. Pick a site on the map to see its calendar, or set a free Campsite Sniper alert. You complete the reservation yourself on Recreation.gov.
Does Campsite Sniper book this campground for me?
No. Campsite Sniper sends alerts and direct Recreation.gov links. It never books, pays for, holds, hoards, or resells reservations.
How current is this availability data?
Campsite Sniper re-checks public Recreation.gov availability for this facility every hour and republishes whenever anything changes. This facility's data last changed at Sep 18, 2026 16:19 UTC; an older timestamp means nothing has changed since that time, not that checking stopped. Always confirm final availability on Recreation.gov when you book.
How often do new openings appear at Castle Flats Cabin?
Campsite Sniper detected 2 site-date openings at Castle Flats Cabin in the last 7 days, 2 over 30 days and 7 over the last 90.
Can I get a multi-night stay at Castle Flats Cabin?
3 three-night openings are showing, counting only runs where the SAME site is free for all three nights. The soonest starts Sep 18 at site P10. Confirm and book on Recreation.gov.
Which month has the most availability at Castle Flats Cabin?
December 2026, with 31 open site-nights in the current snapshot of 31.
When is the next open date at Castle Flats Cabin?
As of the Sep 18, 2026 snapshot: the next open date is Fri, Sep 18 and the next open weekend starts Fri, Sep 18. Detected openings can add earlier dates at any time; a free Campsite Sniper alert catches those the moment they appear.
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