It partly depends on how you define "town"; Kalayaan which is a town on a Pacific has a population of around 200. There are ghost towns in the western states of America that have no inhabitants.
Actually, the town of Alert, Nunavut, Canada has a 2006 population of 5. This could be wrong, the population may be as low as 1 or as high as 10.
Louden
. The least populated town in Brazil is "Serra da Saudade" in the state of Minas Gerais, (825 inhabitants) -
The most least populated city in Kentucky is Bradfordsville.. A little town that population on reaches about 350-400. Oldest person living there is James Mullins. Who served in World War 2.. He is 89
Mongolia is the least densely populated country in Asia, with vast expanses of wilderness and a small population spread across its large territory.
I think it is Dummer which has a population of 335 residents.
Antarctica.
The Pitcairn Islands have a population of around 50 making it the least populated jurisdiction in the world, although it is not a sovereign nation. The Vatican is the world's smallest and least populated country at about 920 people.
Monaco, Singapore and South Korea are the most densely populated countries in the world. Mongolia, Namibia and Australia are least densely populated
Vatican City
Greenland
The Vatican City.
i would have to say Vatican city is the least populated with a population of 821 people.