Population density is a term used to describe the number of people living in a given area, typically measured in square miles or square kilometers. It is calculated by dividing the total population of an area by its total land area. Population density is an important concept in urban planning, social sciences, and environmental studies as it provides insights into how crowded or sparsely populated a particular area is. High population density can lead to challenges such as overcrowding, traffic congestion, and strain on resources, while low population density can impact access to services and infrastructure. Researchers often study population density to better understand patterns of urbanization, migration, and resource distribution.