Population density is a measurement of population per unit area or unit volume; it is a quantity of type number density. It is frequently applied to living organisms, and most of the time to humans.
Cities with high population densities are, by some, considered to be overpopulated, though this will depend on factors like quality of housing and infrastructure and access to resources. Most of the most densely populated cities are in Southeast Asia, though Cairo and Lagos in Africa also fall into this category.
Monaco in Southern Europe, currently holds the record for being the most densely populated nation in the world.
Mongolia is the least densely populated country in the world.
