Population density is the number of people living in a particular amount of space, such as a square mile or square kilometer. It is determined by dividing the population of an area by its land area.
Population density can apply to any size area, from a building to a nation. If an area is densely populated, that means a larger number of people live in a smaller amount of space. If an area is sparsely populated, however, a smaller number of people live in a larger land area. Though population density often refers to people, it can also refer to animals or any living organisms residing in a particular space.