It has its own church, school, workshops, stores, cookhouse, recreation areas and sleeping accommodation. All are built in the solid style of Victorian and Edwardian Britain.
Peninsular Barracks is now empty except for some military museums and many of the buildings are suffering from the effects of the weather. To the anger of conservationists, much of it faces demolition.
Built between the 1850s and the early years of this century, the barracks became the depot for three famous regiments, the Rifle Brigade, the King's Royal Rifle Corps and the Royal Hampshire Regiment. Fifty years ago American soldiers stayed there prior to the D-Day landings.
Now the Ministry of Defence wants to dispose of the site along with hundreds of properties no longer needed by the reduced armed forces. This has raised fears that an important part of Britain's heritage may be
Jocelyn Stevens, chairman of English Heritage, told a Commons select committee earlier this month that the MoD was selling off 'some of the very finest buildings in our history' and that many were in bad condition.
Dockyards, barracks, airfields, forts and laboratories will be redeveloped for shops, housing, hotels, or become tourist attractions. Mr Stevens told MPs that their preservation was 'a very great worry at the moment'.
In Winchester a battle is developing over the future of the 15- acre (6-hectare) site. The MoD has got planning permission for a redevelopment scheme and put the barracks up for sale for an undisclosed price.
The plan is to knock down almost all the buildings in the lower barracks, many dating from the Crimean war, but keep those in the upper barracks, which are newer. Shops, offices and 127 flats and houses would be built along with an underground car-park.
Conservationists have produced a scheme which would preserve the lower barracks and convert the buildings into 104 houses with recreational and cultural facilities, and public gardens.
The preservation scheme is the brainchild of Huw Thomas, an architect whose offices are next to the barracks, and who has the support of the conservation group Save. He argues that to demolish the lower barracks would be 'like having two china dogs and then smashing one of them'.
Since the Army left eight years ago, roofs have begun to leak, saplings have taken root in parapets and rot has set in. He said: 'We could make this really beautiful. But we believe that the area needs to be developed as a whole and we don't have many barracks of this kind left in England.'
The MoD, which is to launch an initiative called 'Defending Our Heritage', is hoping to sell the barracks in the next few months. It says in cases like this it relies on the advice of the local authority about development.
A spokesman said: 'When we sell a piece of land where there is planning permission in place, then it is worth more. That does not necessarily mean that the plan will go ahead but we do have a duty to get the best return we can for the taxpayer.'
David Cowan, chief executive of Winchester City Council, said: 'The MoD's planning application was the only one for the site at the time it was approved. If another came in we might be prepared to grant that also.'
Mr Thomas said: 'Men left these barracks to serve all over the world. How will future generations regard us if we lose this piece of our history for a modern development that you could put anywhere in the city?'