# Population density

(If you were linked from a country article: the density there is based on land area, see below)

Population density can be used as a measurement of any tangible item. However it is most frequently applied to living organisms. Population density is usually expressed in terms of items or organisms per unit area.

## How to define population density?

Note that population density, according to this definition, depends on the scale of the sampling area used, and is hard to define as a real-valued continuous function over the area in question. If the items concerned are modelled as discrete points, the population density will jump up and down as the edge of the sampling area passes over individuals. Modelling the individuals as spatially extended objects has other problems, as the scale of the sampling area approaches the scale of an object (for example, a person's scale may be regarded as the size of the grounds of their dwelling place: for some people, this will be a large area).

To resolve some of these problems, population density may be regarded, like coastline distance, as a scale-dependent fractal quantity.

## Biological population densities

Population density is a common biological measurement and is often used by conservationists as a more appropriate measure than absolute numbers. Low population densities may cause an extinction vortex, where low densities lead to further reduced fertility. This is referred to as the Allee effect, named after W. C. Allee, who first identified it. Examples of this may include;

1. Increased problems with locating mates in areas of low density.
2. Increased inbreeding in areas of low population density.
3. Increased susceptibility to catastrophic events in low population densities.

However it should be noted that different species will have different expected densities. For example r selected species commonly have high population densities, while k selected species may have lower population densities. Low population densities may be associated with specialised mate location adaptations such as specialised pollinators, as is found in the orchid family, (the Orchidaceae.) Insert non-formatted text here

## Human population density

For human beings, population density is the number of persons per unit of area (which may include or exclude inland water), though it may also be expressed in relation to habitable, inhabited, productive (or potentially productive) or cultivated area.

It is frequently measured in persons per square mile or persons per square kilometre or hectare, which can be obtained simply by dividing the number of persons by the land area measured in square miles or in square kilometers or hectares.

Commonly this may be calculated for a county, city, country or the entire world. In the country articles the density is based on land area. However, the list of countries by population density is based on total area, including inland water.

Countries or territories with the highest population densities are:

These territories share a relatively small area and an exceptionally 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.

The most densely populated large state is Bangladesh, where 134 million people live in a highly agricultural area around the lower Ganges river, with a national population density in excess of 900 persons per km�. World overall population density presently averages 42 persons per km�.

Cities with exceptionally high population densities are often considered to be overpopulated, though the extent to which this is the case depends on factors like quality of housing and infrastructure or access to resources. Most of the largest densely-populated cities are in southern and eastern Asia, though Cairo and Lagos in Africa also fall into the category.

City population is however, heavily dependent on the definition used for the urban area: densities will be far higher for the central municipality than when more recently-developed and as yet administratively unincorporated suburbs are included, as in the concepts of agglomeration or metropolitan area, the latter including sometimes neighbouring cities.

## List of countries and their population densities

See also List of countries by population density, which also includes the areas and population numbers.

 Country: Density per sq. Km: Monaco 16329 Singapore 6751 Vatican City 2023 Malta 1249 Maldives 1004.9 Bahrain 987 Bangladesh 926 Barbados 642 Taiwan 627 Mauritius 588 South Korea 491 Netherlands 477 San Marino 448 Tuvalu 423 Lebanon 358 Belgium 338 Israel 335 Japan 335 India 319.3 Marshall Islands 312 El Salvador 307.5 St. Vincent and the Grenadines 300 Sri Lanka 298 Rwanda 281 Philippines 276 Comoros 275 Haiti 271 Vietnam 264 St. Lucia 260 Grenada 259.5 United Kingdom 246 Jamaica 245 Germany 231 Trinidad and Tobago 215 Nauru 213 Burundi 206.1 Liechtenstein 203 Italy 196 Federated States of Micronesia 194 Pakistan 188 Nepal 184 North Korea 182.3 Dominican Republic 178.8 Seychelles 176 Switzerland 176 Luxembourg 171 [[S�o Tom� and Pr�ncipe]] 170 Antigua and Barbuda 152 St. Kitts and Nevis 149 Andorra 144.5 Nigeria 141 Tonga 137 China 134.1 Kiribati 131 Moldova 131 Czech Republic 130 Denmark 125 Poland 123.5 Albania 122 The Gambia 121 Thailand 121 Guatemala 119 Indonesia 119 Kuwait 115 Armenia 112 Portugal 112 Slovakia 111 France 110 Hungary 109 Uganda 105 Serbia and Montenegro 104 Cape Verde 101 Cuba 101 Austria 97 Slovenia 96.9 Syria 93 Dominica 92.8 Romania 91.3 Azerbaijan 90 Malawi 88 Togo 88 Turkey 86.2 Cyprus 83.4 Croatia 83 Ghana 82 Macedonia 81 Greece 80.5 Ukraine 80 Spain 79 Bosnia and Herzegovina 78 Malaysia 76 Sierra Leone 76 Costa Rica 75.1 Cambodia 72.5 Egypt 71 Georgia 71 Lesotho 70.6 Morocco 70 Bulgaria 69.5 Qatar 69 Swaziland 65 East Timor 63.5 Myanmar 62 Brunei 61 Tunisia 60.7 Benin 60 Ethiopia 60 Samoa 60 Uzbekistan 57 Ireland 56 Honduras 55.8 Lithuania 55.1 Iraq 55 Mexico 54 Kenya 53.4 [[C�te d'Ivoire]] 53 Senegal 52 Belarus 50 Guinea-Bissau 48 Jordan 48 Tajikistan 48 Fiji 47 Burkina Faso 46 Bhutan 45 Afghanistan 43 Palau 42 Iran 40 Nicaragua 39.6 Eritrea 37 Latvia 37 Panama 37 Yemen 37 Colombia 36 Ecuador 36 South Africa 36 Cameroon 34 Zimbabwe 32 Estonia 31 United States of America 31 Guinea 30.4 United Arab Emirates 29 Venezuela 27 Madagascar 26.4 Liberia 26.3 Democratic Republic of the Congo 24 Kyrgyzstan 24 Laos 24 Mozambique 23.8 Bahamas 22 Peru 22 Djibouti 21 Brazil 20.7 Chile 20 Sweden 20 Tanzania 20 Uruguay 19 Finland 17.1 Solomon Islands 17 Equatorial Guinea 16.9 Vanuatu 16 New Zealand 15.1 Sudan 15 Argentina 14 Norway 14 Paraguay 14 Algeria 13.3 Zambia 13 Somalia 12.6 Oman 12.3 Belize 12 Saudi Arabia 12 Papua New Guinea 11 Mali 10.9 Turkmenistan 9.4 Angola 8.6 Congo 8.6 Russia 8.5 Bolivia 8 Niger 8 Chad 7.2 Kazakhstan 6 Central African Republic 5.8 Gabon 4.6 Guyana 3.2 Libya 3.1 Australia 3 Canada 3 Iceland 2.8 Botswana 2.7 Suriname 2.7 Mauritania 2.6 Namibia 2.2 Mongolia 1.7 Greenland 0.2