North America · Fortified Structure
Alcatraz Island
United States
Alcatraz places a steep island shoreline and substantial Cellhouse between twenty survivors and San Francisco Bay. Its difficult landing approaches buy separation, while drinking water, food and waste handling remain tied to mainland logistics.
Overall
6 out of 10Defensibility
7 out of 10Isolation
6 out of 10Sustainability
5 out of 10Ranking context
How this base ranks
Global
#11 of 88 · Top 13%
Region · North America
#2 of 9 · Top 22%
Base Type · Fortified Structure
#6 of 18 · Top 33%
Field assessment
At a glance
Bottom Line
A useful contained refuge if water and sanitation can be maintained; secure rooms alone do not make the island a lasting home.
Biggest Trade-off
The same water crossing that limits casual arrival also interrupts the ordinary routes for drinking water, food, fuel and waste removal.
Most Likely Failure
Imported water or food is depleted while waste accumulates; the group must leave an otherwise defensible island to meet basic needs.
Score rationale
Why it scores this way
Defensibility · 7/10
Steep shoreline, controlled entry and the Cellhouse create successive barriers at the occupied boundary. Keep arrivals separate from accommodation; the bay does not contain an infection already brought inside.
Advantages
- Substantial concrete and controlled internal spaces allow separation within the existing built footprint.
Limitations
- Aging structures and the wider island require selective occupation rather than treating every room and shoreline point as secure.
Isolation · 6/10
A real water crossing blocks ordinary land movement, but the island sits beside a major metropolitan population. This is separation from nearby pressure, not distance from it.
Advantages
- There is no land connection through which ordinary ground traffic can reach the island.
Limitations
- Boats can cross the bay, so nearby urban activity still matters when assessing arrivals.
Sustainability · 5/10
There is extensive shelter and documented utility infrastructure, but current use depends on deliveries and waste export. Power generation helps daily life without resolving the island’s water and food dependencies.
Advantages
- Existing sheltered circulation and rooms give twenty people a usable physical framework for shared living.
Limitations
- Imported drinking water and external provisioning must be distinguished from the storage and service points already on the island.
Survival horizons
How survival changes over time
Control arrival and inventory
First 7 Days
Inspect usable Cellhouse rooms and the dock route, account for accessible water and food, and verify sanitation before assuming the island can support occupation.
Positive factors
- The dock-to-Cellhouse route gives arrivals a defined path to monitor and manage.
Risks
- Former support rooms and visible utility equipment do not establish safe, functioning services.
Balance use and waste
First 100 Days
Monitor water drawdown, battery performance and essential power use while establishing what can realistically happen to waste without routine mainland removal.
Positive factors
- Multiple documented electrical pathways offer options if their equipment and inputs remain usable.
Risks
- Continued electrical service does not replenish drinking water or remove sewage.
Resolve the mainland dependency
Long Term
Long-term residence needs dependable potable water, food and sanitation within the approved boundary. No independent replacement system is established by the evidence.
Positive factors
- The island’s passive barriers remain useful without consuming generator fuel.
Risks
- Resource renewal and structural upkeep can force repeated external journeys, exposing the group despite its strong home position.
Visual survey
Gallery
Location context
The Lay of the Land
Tactical assessment
Practical Reality
Best Use
Keep the occupied area close to usable Cellhouse space and the dock route, with arrivals assessed before they enter shared accommodation.
Strengths
- The dock route and steep shoreline concentrate practical arrival points, helping a small group observe contact before it reaches occupied rooms.
- The substantial Cellhouse offers room to separate sleeping, storage and internal isolation without adding new buildings.
- Documented solar, battery and diesel power provides more than one electrical pathway, subject to equipment condition and available inputs.
Key Risk
Waste export and drinking-water delivery serve different needs, but both depend on a mainland connection the group cannot assume will continue.
Weaknesses
- Drinking water is delivered from the mainland; an island refill point is a distribution facility, not a water source.
- Food provisioning and waste removal rely on external services, leaving everyday habitation dependent on the crossing.
- Heritage structures require stabilization, and former institutional rooms cannot all be assumed safe or usable.
Reality Check & Constraints
Twenty capable adults inherit surviving structures, not a staffed prison. Former kitchens and medical rooms are not evidence of working equipment, clinical capability or available supplies.
Assumptions / constraints
- The group comprises twenty capable adults without guaranteed ferries, boats, NPS staff or historic prison personnel.
- Solar equipment, batteries, diesel, stored water and food require inspection or inventory; no operating duration is inferred from installed capacity.
Decision context
Rivals / Alternatives
Similar rival
Fort Jefferson
United States · Fortified Structure
Fort Jefferson keeps the same fortified structure strategy, with only 0.7 points between the overall scores and closely matched isolation pressure.
Overall 6.7/10
Strongest alternative
Fort George
United Kingdom · Fortified Structure
Fort George scores 6.7 overall versus 6.0, adding a stronger sustainability profile while staying relevant as another fortified structure.
Overall 6.7/10
Wildcard rival
Great Mosque of Djenné
Mali · Landmark Structure
Great Mosque of Djenné changes the strategy: it is built around the landmark structure strategy without a headline-pillar edge over Alcatraz Island, while Alcatraz Island holds more of the isolation advantage.
Overall 1.3/10