Population density is the number of people per unit of area, usually
expressed as people per square kilometer (per km2) or people
per square mile (per mi2). To calculate population density,
divide the number of people in an area by the size of the area.
For example, a city has 10,000 people, and an area of 10 square miles.
To calculate the density, do the following:
people = 10,000
area = 10 square miles
density = 10,000 ÷ 10 square miles = 1,000 per mi2
Population density is the measure of how crowded an area is. In the
USA, the average population density for a city is 4,300 per
mi2. The USA as a whole has a population density of 91
per mi2. The average city has a much higher density than the
entire country because cities are much more compact with less empty
land.