Density is population divided by area
Population density expresses how many residents correspond to a unit of geographic area. This publication divides the July 1, 2025 resident population by matching 2025 land area and reports people per square mile. Water area is excluded. The calculation uses unrounded values and rounds the displayed result to one decimal place.
A place with an illustrative 100,000 residents and 50 square miles of land has a density of 2,000 people per square mile. That average does not say every square mile contains 2,000 people. Residents can be concentrated in one part of the unit, while another part contains parks, industry, agriculture or undeveloped land.
Use a compatible boundary vintage
The numerator and denominator must describe the same geographic unit. The initial PEP series uses January 1, 2025 boundaries. Land area is joined from the Census 2025 Gazetteer by official code, rather than a place name. A failed area join suppresses density; missing area is not filled with zero and a county area is not substituted for a city area.
An annexation or reorganization can change a unit's area and population coverage. Comparing current density with a historical density computed on an older boundary can mix demographic change with geographic change. A standardized-boundary history requires documented crosswalks or spatial estimates; a visual trend alone does not establish compatibility.
Compare like units
A compact city proper and a broad county represent different areas. Metropolitan regions contain whole counties and can include extensive less-dense land. Urban areas have a different definition again. A city's density rank is meaningful only within the stated eligible city universe and area rule.
Consolidated governments and balance records require separate definitions. A balance may exclude separately incorporated places and therefore have a different numerator and denominator from an entire consolidated government. This site's ordinary-place rankings exclude those balances rather than averaging unlike categories.
Combining areas and mapping
For a region formed from nonoverlapping counties, sum the population and compatible land area before dividing. Do not average individual densities, because a large county and a small county should not automatically receive equal weight. Map density with normalized shading and an explicit legend; population totals are better represented by appropriately scaled symbols where practical.
A density figure is not evidence of neighborhood suitability or an individual's traits. Use the exact geographic definition, source date and area vintage when citing it. See Census Gazetteer documentation, the site methodology, and the state map with table alternative.