The most populous unincorporated areas have all of the standard amenities: https://en.wikipedia.org/wiki/Bel_Marin_Keys,_California https://en.wikipedia.org/wi

The most populous unincorporated areas have all of the standard amenities: https://en.wikipedia.org/wiki/Bel_Marin_Keys,_California https://en.wikipedia.org/wiki/Bel_Marin_Keys,_California That's an unincorporated area, populated by an affluent community, with all the services you'd expect. I think the answer is actually in the negative becuase the common amenities include pretty basic services like roads, police protection, or grid power. As far as I'm aware that level of disconnect is very rare.