Population Density
Definition
The number of people per unit of land area, typically expressed as people per square mile (US) or people per square kilometer (international).
Why It Matters
Population density shapes urban planning, infrastructure needs, housing markets, and quality of life. High-density areas need more public transit, vertical housing, and shared spaces. Low-density areas require more road infrastructure and car dependence.
How It's Measured
Calculated by dividing total population by total land area. Water areas are excluded.
Current Value
US average: approximately 94 people/sq mi; NYC: 28,000/sq mi; Wyoming: 6/sq mi
Related Terms
Frequently Asked Questions
The number of people per unit of land area, typically expressed as people per square mile (US) or people per square kilometer (international).
Population density shapes urban planning, infrastructure needs, housing markets, and quality of life. High-density areas need more public transit, vertical housing, and shared spaces. Low-density areas require more road infrastructure and car dependence.
Calculated by dividing total population by total land area. Water areas are excluded.
this entity is one of the U.S. population demographics concepts that recurs across this site. The definition above is the technical answer; the paragraphs below add the practical context for how the concept connects to the the U.S. Census Bureau ACS and decennial files data behind every per-entity page on the site.
In the the U.S. Census Bureau ACS and decennial files data, this concept shapes one or more of the fields that drive the per-entity grades and rankings on this site. The methodology page describes which fields feed into which output; this glossary entry documents the underlying term.
Source: U.S. Census Bureau ACS, 2026.