# Population density

Population density (people per km2) by country, 2012.
Population density (people per km2) by country, 2006.
Population density (people per km2) map of the world in 1994 (detailed).
Population density (people per km2) map of the world in 1994.
Deserts around the world. Compare with maps above. See also this image for location of densely populated areas (cities) in various vegetation zones.

Population density (in agriculture : standing stock and standing crop) 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 particularly to humans. It is a key geographic term.[1]

Lists of population density of different countries are below. Lists of other population densities are in See also section.

## Biological population densities

Population density is population divided by total land area or water volume, as appropriate.[1]

Low densities may cause an extinction vortex and lead to further reduced fertility. This is called the Allee effect after the scientist who identified it. Examples of the causes in low population densities include:[2]

• Increased problems with locating sexual mates
• Increased inbreeding

## Human population density

Monaco in South 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.
This population cartogram of Europe uses areas and colors to represent population.

For humans, population density is the number of people per unit of area, usually quoted per square kilometer or square mile (which may include or exclude, for example, areas of water or glaciers). Commonly this may be calculated for a county, city, country, another territory, or the entire world.

The world's population is around 7 billion,[3] and Earth's total area (including land and water) is 510 million square kilometers (197 million square miles).[4] Therefore the worldwide human population density is around 7 billion ÷ 510 million = 13.7 per km2 (35 per sq. mile). If only the Earth's land area of 150 million km2 (58 million sq. miles) is taken into account, then human population density increases to 47 per km2 (120 per sq. mile). This includes all continental and island land area, including Antarctica. If Antarctica is also excluded, then population density rises to over 50 people per km2 (over 130 per sq. mile).[1] However over half[citation needed] of the Earth's land mass consists of areas inhospitable to human habitation, such as deserts and high mountains, and population tends to cluster around seaports and fresh water sources. Thus this number by itself does not give any helpful measurement of human population density.

Several of the most densely populated territories in the world are city-states, microstates, and dependencies.[5][6] These territories have a relatively small area and a high urbanization level, with an economically specialized city population drawing also on rural resources outside the area, illustrating the difference between high population density and overpopulation.

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.[7] Most of the most densely populated cities are in southern and eastern Asia, though Cairo and Lagos in Africa also fall into this category.[8]

City population and especially area are, however, heavily dependent on the definition of "urban area" used: densities are amost invariably higher for the central city area than when suburban settlements and the intervening rural areas are included, as in the areas of agglomeration or metropolitan area, the latter including sometimes neighboring cities. For instance, Milwaukee has a greater population density when just the inner city is measured, and the surrounding suburbs excluded.[9]

In comparison, based on a world population of seven billion, the world's inhabitants, as a loose crowd taking up ten square feet (one square metre) per person (Jacobs Method), would occupy a space a little larger than Delaware's land area.

## Most densely populated countries/regions

### By inhabited region

RegionPopulationArea (km2)Density
(Pop. per km2)
Indo-Gangetic Plain (Pakistani Punjab to Bangladesh and Assam)1 billion1,000,0001000
Greater North China Plain600 million700,000857
Sichuan Basin110 million250,000440
Java Island145 million130,0001115
Taiheiyo Belt (Japan)85 million60,0001417
SE China coast (Guangdong, Hong Kong, Fujian)140 million100,0001400
Nile Delta50 million50,0001000
Southern India (Tamil Nadu, Pondicherry, Bengaluru, and Kerala)120 million170,000706
West Indian Coast (Maharashtra and Gujarat Coast)70 million100,000700
Northern Europe (Benelux, North Rhine-Westphalia)44 million110,000400
NE US Coast45 million100,000450
S Central England40 million60,000667
Central Mexico40 million100,000400
Luzon Island50 million105,000476
South Korea50 million100,000500
Southeastern Brazil Coast50 million100,000500

### By political boundaries

With population above 1 million
RankCountry/RegionPopulationArea (km2)Density
(Pop. per km2)
1 Singapore5,183,7007107301
2 Hong Kong7,061,2001,1046396
3 Gaza Strip1,816,3793605045
4 Bahrain1,234,5967501646
6 Taiwan (R.O.C)23,361,14736,190646
7 Mauritius1,288,0002,040631
8 South Korea50,219,66999,538505
9 Lebanon4,966,00010,452475
10 Rwanda10,718,37926,338407
With population above 10 million
RankCountry/RegionPopulationArea (km2)Density
(Pop. per km2)
2 Taiwan (R.O.C)23,361,14736,190646
3 South Korea50,219,66999,538505
4 Rwanda10,718,37926,338407
5 Netherlands16,760,00041,526404
6 India1,249,500,0003,185,263392
7 Haiti10,413,21127,750375
8 Belgium11,007,02030,528361
9 Japan127,290,000377,944337
10 Philippines100,271,800300,076334

## Other methods of measurement

While arithmetic density is the most common way of measuring population density, several other methods have been developed which aim to provide a more accurate measure of population density over a specific area.

• Arithmetic density: The total number of people / area of land (measured in square miles or square kilometers ).
• Physiological density: The total population / area of arable land.
• Agricultural density: The total rural population / area of arable land.
• Residential density : The number of people living in an urban area / area of residential land.
• Urban density : The number of people inhabiting an urban area / total area of urban land.
• Ecological optimum: The density of population which can be supported by the natural resources.

## References

1. ^ a b c Matt Rosenberg Population Density. Geography.about.com. March 2, 2011. Retrieved on 2011-12-10.
2. ^ Minimum viable population size. Eoearth.org (2010-03-06). Retrieved on 2011-12-10.
3. ^ U.S. & World Population Clocks. Census.gov. Retrieved on 2011-12-10.
4. ^ World. CIA World Handbook
5. ^ Department of Economic and Social Affairs Population Division (2009). "World Population Prospects, Table A.1" (PDF). 2008 revision. United Nations. Retrieved 2009-03-12.
6. ^ The Monaco government uses a smaller surface area figure resulting in a population density of 18,078 per km2
7. ^ Human Population. Global Issues. Retrieved on 2011-12-10.
8. ^ The largest cities in the world by land area, population and density. Citymayors.com. Retrieved on 2011-12-10.
9. ^ The Population of Milwaukee County. Wisconline.com. Retrieved on 2011-12-10.