By "Terra Nullius" or "white spot" I mean a place where you (if you were so inclined) could "legally" settle and live in some wilderness as a trapper or farmer without having to ask for permission, pay taxes, etc. (A place where you could get away with anarchy, if you will.)
If you look at today's word map it's clear that all territory belongs to states, which need to support themselves, hence ask duties and raise taxes from their citizens, etc. I once thought that during the settlement of the American Wild West there was still plenty of "white space" left (every rancher is his own king, so to speak), but presumably all its territory was already claimed by the time of, say, the early 19th century? Would there perhaps have been "white space" left e.g. from the point of view of precolonial Indians?
Or did the possibility vanish even earlier? (IMO it must have existed somewhen in the past when population counts were low compared to habitable areas. According to this movie the Last Trapper may be still alive and well ...)