Singapore is the third most densely populated country in the world after Macau (China) and Monaco. If you have ever wondered where the most densely populated area in Singapore is, wonder no more. A blog ‘geodata-musing’ claims that the honour goes to Choa Chu Kang.
The blog said that there are more than 28,000 residents per sq km of land area in Choa Chu Kang town.
But that is before you refine the search into subzones (as defined by URA) by dividing each town planning areas. That honour of being the densest subzone in Singapore goes to Jurong West Central. It has more than 49,000 residents per sq km.
The runner-up is Yew Tee (part of Choa Chu Kang), with more than 48,000 residents per sq km, followed closely by Tiong Bahru.
Full analysis of the various sub-zones here: http://geodata-musing.blogspot.sg