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Diefenbunker / Central Emergency Government Headquarters National Historic Site of Canada

3929 Carp Road, Ottawa, Ontario, K0A, Canada

Formally Recognized: 1994/06/05

Entrance of the bunker with surrounding landscape; Parks Canada | Parcs Canada
Entrance of the bunker
View of a corridor in the bunker; Parks Canada | Parcs Canada
A hallway in the bunker
War cabinet room in the bunker; Courtesy of Canada's Cold War Museum | Gracieuseté du Musée canadien de la Guerre froide
War cabinet room

Other Name(s)

Diefenbunker / siège central du gouvernement d'urgence
Diefenbunker / Central Emergency Government Headquarters National Historic Site of Canada
Diefenbunker / Central Emergency Government Headquarters

Links and documents

Construction Date(s)

1959/01/01 to 1961/01/01

Listed on the Canadian Register: 2006/01/13

Statement of Significance

Description of Historic Place

The Diefenbunker / Central Emergency Government Headquarters National Historic Site of Canada is a large, underground bunker located at Carp (now Ottawa), Ontario, just south of the nation's capital. Located securely just below the peak of a natural ridge, only its metal entrance way tunnel and butler hut, associated antenna farm and perimeter fence are visible on the surface. The Diefenbunker itself is a fortified concrete structure extending four storeys below ground: its air intake and exhaust elements, escape hatches, deep wells and sewage lagoons are disguised in the man-made contours of the surrounding landscape. It is now open to the public as Canada's Cold War museum.

Heritage Value

The Diefenbunker / Central Emergency Government Headquarters was designated a National Historic Site because it is:
- symbolic of the Cold War and the strategy of nuclear deterrence,
- symbolic of Canada's determination to survive as a nation following a nuclear war,
- a poignant and tangible reminder of what was one of the most critical periods in modern history.

The heritage value of the Diefenbunker / Central Emergency Government Headquarters National Historic Site of Canada lies in the comprehensive physical evidence it presents confirming Canada's determination to survive and function as a nation during a nuclear attack as illustrated by its location, disguised setting, defensible design, and the heavily fortified construction. The Diefenbunker was Canada's Central Emergency Government Headquarters during the Cold War. Designed 1957-59, it was built by the Government of Canada in 1959-61 to shelter key political and military personnel in the event of a nuclear attack. It functioned as the hub of a communications network and civil defence system from 1961-1994. The facility originally had two parts - a transmitter building located at Richardson, 45 km south of Carp (now Ottawa), and the main or receiver building situated at Carp. The National Historic Site consists of only the Carp facility.

Source: Historic Sites and Monuments Board of Canada, Minutes, spring and fall 1994, May 1998.

Character-Defining Elements

Key elements contributing to the heritage value of this site include:
- the location just outside the nation's capital in a quiet rural setting;
- its site in a former sand pit with a natural water supply, a porous ground type and natural drainage;
- the grassed, open spaces of the site,
- the completeness of the cultural landscape of the bunker site both above and below ground;
- the bunker's design, scale, systems and materials;
- the found scale, form, materials and profile of its entrance blast tunnel;
- the proportion and invisibility of its thick concrete roof covered with clay loam;
- the massive scale, four-storey underground depth, and designed impenetrability of the bunker;
- its configuration as a hardened concrete box set inside a thick crushed gravel envelope;
- the thick hardened concrete materials of its exterior walls with its heavy steel reinforcing rod and concrete construction technology;
- evidence of the application of naval engineering technology such as the concrete pad, self sufficient systems, elaborate tie-down systems, and emergency escape hatches;
- the special innovative engineering evident in its utility systems (integrated natural water supply, flexible exterior utility connections, independent HVAC, electrical, environmental control, water supply and sewage disposal, radiation and blast detection, fire detection, control and suppression, security, food handling and garbage processing systems together with their duplication and designed redundancy) ;
- the relative placement, size and organization of functions on the interior of the building (the vault, office, meeting, and sleeping spaces for 400 people, communications areas including a CBC studio);
- the late 1950s and early 1960s manufactured materials present in interior fittings and furnishings (linoleum, asbestos tile, aluminum, concrete);
- evidence of Modernist interior design in the use of colour in interior spaces;
- the high quality maintenance of technological equipment (utility, computer and communications);
- the disguised integration service features in the surrounding landscape (air exhaust and intake vents, escape hatch lids, cloudbursts and tunnel portals);
- the undisguised features of the landscape (the antenna farm, the perimeter fence, roadways, parking lots, helicopter pad);
- the relative placement, scale, design, materials, functions and special properties of surrounding buildings associated with the operations of the bunker (the guard house and related shelter, the underground garage, the fibreglass tuning hut, the underground communications vault);
- archaeological remains of once-associated buildings, cables, roadways, antennae and sewage lagoons in the area surrounding the bunker.




Recognition Authority

Government of Canada

Recognition Statute

Historic Sites and Monuments Act

Recognition Type

National Historic Site of Canada

Recognition Date


Historical Information

Significant Date(s)

1961/01/01 to 1994/01/01

Theme - Category and Type

Governing Canada
Government and Institutions
Governing Canada
Military and Defence

Function - Category and Type



Military Defence Installation

Architect / Designer

Government of Canada



Additional Information

Location of Supporting Documentation

Indigenous Affairs and Cultural Heritage Directorate Documentation Centre 3rd Floor, room 366 30 Victoria Street Gatineau, Québec J8X 0B3

Cross-Reference to Collection

Fed/Prov/Terr Identifier




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