So you can build a house in the middle of a street?

If someone tries to stop you, by what authority? If they can stop you, there's your government.

More than 100,000 people?

Even Kowloon had a degree of management by criminal groups.

I'm not claiming there is literally no government, I'm claiming they are not acting in planning or maintenance ('civil management') capacity. If you have an easement contract to travel on a 'street' and someone violates it by building a house on it you can still sue them but the government has nothing to do with planning that. The population is not quite 100k but also not an order of magnitude lower either.

But you don't have to pay them even if you lose the suit. No police. If they try to take by force you can defend your property and your life.

Yeah this has happened, where someone went into the easement. Though with fences instead of houses. People just drive around. Realistically no one has decided to die over a fence or house being in the way and no one has decided to die over blocking a car from going around. It's one of those thought exercises that sounds interesting but isn't actually an issue.

Now I suppose at this point you'll move on to the next goal posts. We've been deregulated for 20+ years and we got this long list of gotchas by the statists when we did it but none of the hysterical hypothetical happened and largely because anyone capable of feeding themselves soon realizes acting in extreme bad faith in a place without police is worse for them than it is the people around them. You can add all the 'but but' whatubaut this and that but it simply isn't any more a problem than the fact we also haven't installed anti-aircraft lasers in case aliens arrive.

What an odd tangent.

Perhaps if you named the place I would be more able to assess information.

I have little to go on, when you say privately owned? By whom?

Is the ungoverned nature recognised by the country within which it resides?