Population Density by City: 2020 Census Rankings for U.S. Cities and Metros

Population density—the number of people per square mile—offers one of the clearest lenses on how Americans live, build, and use land. The 2020 Census reveals a striking pattern: the densest places in the United States are not necessarily the largest cities, but often small municipalities and census-designated places in the Northeast, where compact geography and multifamily housing push densities above 50,000 people per square mile. At the top, Friendship Heights Village, Maryland, a census-designated place bordering Washington, D.C., recorded about 90,780 people per square mile, far exceeding the density of major cities like New York or San Francisco. This article breaks down the official 2020 Census rankings, explains how density is measured, and explores what these numbers mean for urban policy and daily life.

Key Numbers

• Highest density place: Friendship Heights Village CDP, MD — 90,780 people per sq mi
• Second highest: Guttenberg town, NJ — 62,260 people per sq mi
• Third highest: Union City city, NJ — 53,290 people per sq mi
• Fourth highest: West New York town, NJ — 53,220 people per sq mi
• Total U.S. urban population (2020): 265,149,027
• Share of Americans in urban areas: 80.0%
• Urban area density change, 2010–2020: +9.0%
• Number of 2020 Census urban areas: 2,611

Explanation

Population density is calculated by dividing the total resident population of a place by its land area in square miles. The U.S. Census Bureau recognizes two main types of places: incorporated places, which have their own local government, and census-designated places (CDPs), which are unincorporated but statistically defined for data purposes. Because density depends on both population and land area, a small place with a tiny footprint can rank far higher than a large city with a much bigger population. For example, Friendship Heights Village has a population of only a few thousand but covers less than 0.1 square mile, producing an extremely high density.

The 2020 Census counted 265,149,027 people living in urban areas, or 80.0% of the U.S. population. Urban areas themselves became denser between 2010 and 2020, with population density rising 9.0% even as urban land area shrank by 2.4%. This densification reflects infill development, redevelopment of older neighborhoods, and constraints on outward expansion in many metro regions.

At the city and place level, the densest locations are concentrated in the New York metropolitan area and nearby counties in New Jersey and New York. These places often have long histories of high-rise apartment buildings, small lot sizes, and proximity to transit, which allow many residents to live in a compact area.

Definition

In U.S. Census data, population density is expressed as people per square mile of land area. Water area is excluded from the calculation. The Census Bureau publishes density for incorporated places (cities, towns, boroughs, villages) and for census-designated places (CDPs), which are unincorporated communities that lack separate local government but are recognized for statistical purposes. Urban areas are separately defined as densely developed territory with at least 2,000 housing units or 5,000 people, and they can cross city and county boundaries.

Ranking Table

The table below shows the top four U.S. places by population density from the 2020 Census, based on data compiled by BeautifyData from official Census 2020 files. All values are people per square mile.

Other places that appear in the top 10 include Hoboken, New Jersey; Kaser, New York; Cliffside Park, New Jersey; and New Square, New York. These communities are all small in land area and located in the densely developed corridor around New York City.

State Comparison

New Jersey stands out in the 2020 density rankings, with multiple municipalities in the top 10, including Guttenberg, Union City, West New York, Hoboken, and Cliffside Park. These Hudson County towns sit directly across the Hudson River from Manhattan and have some of the highest concentrations of multifamily housing in the country. New York also contributes several high-density places, particularly in the Hasidic villages of Kaser and New Square in Rockland County, where large households and very small municipal boundaries produce extreme densities. Maryland appears at the very top through Friendship Heights Village, a CDP on the Washington, D.C., border. No state outside the Northeast or Mid-Atlantic appears among the very highest-density places in the available 2020 rankings.

National Comparison

While the top places exceed 50,000 people per square mile, the national picture is far more spread out. The 2020 Census identified 2,611 urban areas in the United States, containing 265.1 million people—80% of the population—on a relatively small share of the nation’s land. The remaining 66.3 million people lived in rural areas. Urban population density increased 9.0% from 2010 to 2020, even as total urban land area declined 2.4%, meaning existing urban areas absorbed most population growth. This national trend contrasts with the extreme local densities in small municipalities, where land area is fixed and housing is overwhelmingly multifamily.

Methodology

The 2020 Census counted every person living in the United States as of April 1, 2020. For each place, the Census Bureau reports total population and land area in square miles. Population density is then calculated as total population divided by land area. The rankings cited here use official 2020 Census data as compiled by BeautifyData, which includes both incorporated places and census-designated places with densities above 10,000 people per square mile. The Census Bureau’s urban area definitions are based on housing unit density and population thresholds, not municipal boundaries, so urban area density can differ from city density.

Why It Matters

Population density is a key indicator for planning and policy. High-density places require different infrastructure—transit, water, sewer, emergency services—than low-density suburbs or rural areas. Density also affects housing costs, energy use, public health, and environmental impact. Compact, walkable communities can reduce car dependence and greenhouse gas emissions, but they also face challenges such as overcrowding, higher land prices, and strain on public services. Understanding which places are densest helps local governments allocate resources and plan for growth.

Factors Behind the Trend

Several historical and geographic factors explain the 2020 density rankings. The Northeast was settled and urbanized before the automobile era, producing street grids, small lots, and apartment buildings that persist today. Many high-density New Jersey municipalities were incorporated in the 19th century with boundaries of less than one square mile, so even modest populations yield high densities. Proximity to New York City and Washington, D.C., has sustained demand for housing in these areas. In some religious communities, such as Kaser and New Square, large family sizes and cultural preferences for walking distance to synagogues and schools further increase density.

Limitations of the Data

Population density rankings can be misleading when comparing places of very different sizes. A CDP like Friendship Heights Village may have only a few thousand residents, so its density reflects a tiny, apartment-heavy enclave rather than a typical city. Municipal boundaries are historical and sometimes arbitrary; a city that annexes surrounding land will see its density fall even if its core remains dense. Census counts are also subject to undercounts, particularly in dense, renter-heavy, or immigrant communities. Finally, density alone does not capture the quality of life, housing conditions, or the functional density of a broader metro area.

10-Year Change

Between 2010 and 2020, U.S. urban areas became denser. The Census Bureau reports that urban population density increased by 9.0%, while urban land area decreased by 2.4%. Total urban population grew 6.4%, from 249.3 million in 2010 to 265.1 million in 2020. This means that population growth was absorbed largely within existing urban footprints rather than through sprawling new development. At the local level, many of the densest places in 2020 were also dense in 2010, reflecting the persistence of compact housing patterns in older Northeastern communities.

Source & Data Date

Primary data come from the U.S. Census Bureau, 2020 Census, with population and housing counts as of April 1, 2020. The city and place density rankings are compiled by BeautifyData from official 2020 Census files and updated February 1, 2026. Urban area statistics are from the Census Bureau’s 2020 Census Urban Areas Facts, updated June 2023. Additional context on incorporated places and census-designated places is drawn from the Census Bureau’s geographic definitions and the Wikipedia list of U.S. cities by population density.