Which of these countries has the smallest population?
To find the world’s smallest city, you’ll need to look for the world’s smallest country as well. You can find them both—Vatican City is in fact a country and a city—encircled by Rome, Italy. At only 0.17 square miles (0.44 square km), the tiny city-state is not even a quarter of the size of the next smallest country, Monaco.
Though every country defines the word "city" differently, meaning some cities host populations of only a handful of residents, Vatican City is generally considered to be the smallest city by population size as well as by area. It has a population of only about 800 people, just over half of whom are citizens. However, many who do have Vatican City passports actually live abroad, working in diplomatic posts.
Priests, nuns, cardinals, and members of the Pontifical Swiss Guard (who have protected the Vatican officially since 1506, and do so still while wearing distinctive orange and blue striped uniforms) make up a large portion of those who reside in the city-state. The most famous resident, of course, is Pope Francis, who also serves as the monarch of the tiny country.