The formula for calculating population density requires dividing the area occupied, typically in square miles or square kilometers, by the number of people living there. Though population density usually refers to people, the term also applies to animals in a particular habitat.
A densely populated area is one where many people live relative to the amount of space in which they dwell. A sparsely populated area has few people relative to the available area. A very large population or a very small area are factors contributing to denser population, whereas a very small population or a very expansive area contribute to a sparser population. As of 2012, New Jersey was the most densely populated state in the nation with 451.99 people per square kilometer, and Alaska was the most sparsely populated state with 0.46 people per square kilometer.