Macau, a special administrative region of China, is 31.3 square kilometers in size (or 12.1 square miles). Some sources quote the area as 28.2 square kilometers.
Macau's small size, and its relatively large population (in the region of 614,000 to 624,000) makes the most densely populated territory in the world. Around 21,000 people live in each square kilometer, around three times greater than Singapore and ten times the population density of Italy.
Would Macau Be The Smallest Country in the World?
Were Macau a separate and autonomous sovereign state, it would be one of the five smallest countries in the world, with only Tuvalu, Nauru, Monaco and The Vatican smaller in size.
As it is, San Marino is the fifth smallest country in the world, at 61 square kilometres (24 square miles).
To give you some idea of Macau's small size, it would cover roughly one-sixth the area of Washington DC.
This YouTube user has filmed a tribute to 'Micro Macau', hopefully it should give you an idea of the place: