Which province or city is the most populous in Vietnam today?

Thanh Hoa is the third most populous locality in the country, after two centrally-run cities, and the first among all provinces. Specifically, Thanh Hoa's population is more than 3.7 million people. Thanh Hoa's average population density is 335 people/km2.

According to Thanh Hoa Information Portal, the population of this province is unevenly distributed among administrative units, between plains and mountainous areas. The population is mainly concentrated in cities, towns, coastal and riverside towns and sparsely in mountainous areas.

Specifically, the population density in Thanh Hoa city is 2,400 people/km2; in Hau Loc, Hoang Hoa, and Quang Xuong districts, it is over 1,100 people/km2. Meanwhile, in mountainous districts such as Muong Lat, Quan Son, and Quan Hoa, the population density is around 40 people/km2.