Are there any official places or towns that are inhabited by only one person?

The answer is Yes!

Unfortunately the first person I was able to find was a man in Russian near Evenkia, who was the only inhabitant of an island at Russia’s geographic center who unfortunately for this answer passed away in mid 2003.

http://english.pravda.ru/main/2003/04/02/45488.html

But upon some further digging I found that you could in fact be that person. According to Land Quest Realty, the host of, the site below there is “Entire B.C. (British Columbia) town for sale for $7M [in which] a caretaker, the town's only inhabitant, keeps lawns and boulevards cut”.

http://www.landquest.com/resources/StarPhoenix-Sept14-2004.htm

So there you have it for just 7 million dollars (maybe Canadian dollars which would be cheaper for US residents) you could be the answer to your own question.


An answer for just the United States:
However, to preface the next part of my answer I must say that I can only answer with my knowledge of the United States census system and this answer while vague may not apply to anywhere else.

The first problem is that, there is not any town that has only one person because the census bureau defines a town as: “A type of minor civil division in the New England states, New York, and Wisconsin; a type of incorporated place in 30 states and the Virgin Islands of the United States. In New Jersey, Pennsylvania, and South Dakota, towns are incorporated places that are not part of any minor civil division, and the Census Bureau treats them as county subdivisions as well as places for data presentation purposes.” In this definition we see the distinction that the place is incorporated which means that it has a fair number of people (or at least enough to be worth counting).

The second problem is that any divisions of land by states (once again in the US only) that have a population of even 5 or under would be unincorporated. This means that there would be no record of this person or even the place that they inhabit.

And for one last shot that is not even close to the intention of your question an estate is considered an official place by the census bureau so a person living in their home alone would then be considered the only inhabitant of that place.