Housing Unit Density by State: Units per Square Mile (2025)

Few statistics capture the uneven geography of American housing as sharply as housing unit density. In 2025, New Jersey packed roughly 439 housing units into every square mile, while Alaska had less than one unit per square mile. The national average was about 39 units per square mile, but that figure hides a range of more than 400 units between the densest and most sparsely settled states.

Key Numbers

• Densest state: New Jersey, 438.8 housing units per square mile
• Second densest: Massachusetts, 291.1 units per square mile
• Third densest: Connecticut, 281.1 units per square mile
• National average: about 39 housing units per square mile
• Most housing units: California, 14,995,410 units
• California density: 91.6 units per square mile, despite having the most units
• Least dense states: Alaska, Wyoming, and Montana, each below 4 units per square mile
• Range: more than 400 units per square mile between the highest and lowest state densities

Explanation

Housing unit density measures how many residential units are located within a given area, typically one square mile. It is calculated by dividing a state’s total housing units by its land area or total area. A housing unit is a house, apartment, mobile home, or other structure intended for separate living quarters. Density is a key indicator of how intensively land is used for housing and how concentrated residential development is across a state.

Unlike population density, which counts people, housing unit density counts physical residential structures. Because the average U.S. household has more than two people, population density is usually higher than housing unit density. For example, New Jersey’s population density is about 1,200 people per square mile, but its housing unit density is about 439 units per square mile. The gap reflects average household size and the presence of nonresidential land.

The 2025 estimates from the U.S. Census Bureau show that housing unit density is highest in the Northeast and Mid-Atlantic, where small states with long settlement histories and limited land area concentrate many homes. It is lowest in Alaska, the Mountain West, and the Great Plains, where large land areas and low population levels spread housing units thinly across the landscape.

Definition

Housing unit density is the number of housing units per unit of area, usually expressed as units per square mile. It is a measure of residential development intensity. A housing unit may be occupied or vacant; the Census Bureau counts all units, whether they are single-family homes, apartments, condominiums, or mobile homes. Density can be calculated using total area, which includes water, or land area, which excludes lakes, rivers, and coastal waters. Most state-level comparisons use land area to avoid understating density in states with large water surfaces, but total area is also common.

How the Statistic Is Calculated

The formula is straightforward: divide the total number of housing units by the area in square miles. For example, New Jersey had 3,827,726 housing units on July 1, 2025, and a total area of 8,722.58 square miles. Dividing the two gives 438.8 housing units per square mile. If land area is used instead, New Jersey’s density rises above 500 units per square mile because the state has significant coastal and inland water area.

The U.S. Census Bureau produces annual housing unit estimates for the nation, states, and counties as part of its Population Estimates Program. The July 1, 2025, estimates are the most recent vintage and are revised each year to reflect new construction, demolitions, and changes in the housing stock. For this article, density figures are calculated using total area in square miles, as reported by the Census Bureau and compiled by World Population Review.

State Comparison

State housing unit densities fall into clear regional patterns. The densest states are concentrated in the Northeast and Mid-Atlantic: New Jersey, Massachusetts, Connecticut, Maryland, New York, and Pennsylvania all rank in the top seven. These states combine relatively small land areas with large, long-established housing stocks. Florida is the only Southern state in the top five, reflecting its high-rise coastal development and large number of housing units relative to its moderate land area.

At the other end, the least dense states are in the West and Great Plains. Alaska, Wyoming, Montana, North Dakota, and South Dakota all have fewer than 6 housing units per square mile. New Mexico, Idaho, Nevada, and Utah also rank near the bottom. These states have vast land areas and relatively small housing stocks, so even moderate numbers of units are spread over hundreds of thousands of square miles.

California is a notable case: it has the most housing units of any state, 14,995,410, but its density is only 91.6 units per square mile because it is the third-largest state by area. Texas, the second-largest state by area, has 12,848,245 housing units and a density of about 48 units per square mile. This shows that total housing units and housing density are not the same thing.

National Comparison

The United States as a whole had about 146 million housing units in 2025, spread across roughly 3.8 million square miles of total area. That yields a national average of about 39 housing units per square mile. The average is pulled down by Alaska, which accounts for more than 17 percent of U.S. land area but less than 0.3 percent of housing units. Excluding Alaska, the national average would be higher, but still far below the densities of the Northeast.

Compared with other countries, the United States has a low housing unit density overall, but this hides enormous internal variation. The contrast between New Jersey and Alaska is starker than the difference between many countries. Within states, density also varies widely: urban counties can have thousands of housing units per square mile, while rural counties may have fewer than one.

Ranking Table

The table below shows the 15 states with the highest housing unit density in 2025, based on July 1, 2025, housing unit estimates and total area in square miles.

The next table shows the lowest housing unit densities among states with available July 2025 housing unit totals in the QuickFacts excerpt. Alaska, Wyoming, Montana, North Dakota, and South Dakota are not shown but have densities below 6 units per square mile.

Factors Behind the Trend

Several factors explain why housing unit density varies so much by state. Historical settlement patterns are important: the Northeast was settled earlier and developed compact towns and cities before the automobile enabled suburban sprawl. States like New Jersey and Massachusetts have many older, densely built municipalities. In contrast, Western states were settled later and often have large tracts of federally owned land that cannot be developed for housing.

Geography and land area play a direct role. Alaska is larger than Texas, California, and Montana combined, but its harsh climate and remote terrain limit housing development. Wyoming and Montana have small populations spread over enormous areas, so even modest housing stocks produce very low densities. Water area also matters: using total area instead of land area lowers the density of states with large lakes or coastal waters, such as Michigan and Florida.

Zoning and land-use policies also shape density. States with strong local control over zoning may have lower densities in suburban and rural areas, while states with more permissive rules for multifamily housing can achieve higher densities. Economic factors, such as job growth and housing demand, influence where new units are built, but they do not always overcome the constraints of land area and geography.

Why It Matters

Housing unit density is a practical statistic for planners, policymakers, and researchers. It helps identify where housing is concentrated and where it is sparse, which affects infrastructure needs, transportation planning, and emergency service delivery. Dense states often face different challenges than sparse states: traffic congestion, high land costs, and aging infrastructure versus long travel distances, limited public transit, and higher per-capita costs for roads and utilities.

Density also has environmental implications. Compact development can preserve open space and reduce per-household energy use, but it can also strain water, sewer, and green space. Low-density development may consume more land per housing unit and increase reliance on cars. Understanding state-level density is a first step toward comparing these trade-offs across the country.

Limitations of the Data

Housing unit density is a useful summary measure, but it has limitations. First, it is an average for an entire state and masks wide variation within states. New York State’s density of 160 units per square mile includes both New York City, where density exceeds 10,000 units per square mile in some neighborhoods, and the Adirondack Park, where density is near zero. Second, the choice of total area versus land area changes the ranking for states with significant water area. Third, housing unit estimates are revised annually and may not capture very recent construction or demolitions perfectly.

Finally, density counts all housing units, including vacant ones. A state with many seasonal or vacation homes, such as Maine or Vermont, may have a higher housing unit density than its year-round population density would suggest. Despite these caveats, the statistic provides a clear, comparable snapshot of residential development intensity across states.

Historical Data

The Census Bureau’s housing unit estimates show that the U.S. housing stock has grown every year since the 2020 census. Between April 1, 2020, and July 1, 2025, the nation added several million housing units, with the largest numerical gains in Texas, Florida, and California. However, because these states also have large land areas, their housing unit densities did not increase as dramatically as in smaller states with strong construction activity.

State-level density rankings have remained relatively stable over time. The Northeast and Mid-Atlantic have held the top positions for decades, while Alaska, Wyoming, and Montana have consistently ranked at the bottom. The main change in recent years has been a gradual increase in density in fast-growing Sun Belt states such as Florida, North Carolina, and Georgia, though they still trail the densest Northeastern states by a wide margin.

Methodology

The housing unit totals in this article come from the U.S. Census Bureau’s QuickFacts, which reports July 1, 2025, housing unit estimates from the Vintage 2025 population estimates program. Total area figures are from the Census Bureau and are compiled by World Population Review. Density is calculated by dividing each state’s housing units by its total area in square miles. The national average is based on the total U.S. housing stock and total U.S. area. All figures are subject to revision in future vintages.

Source & Data Date

Primary source: U.S. Census Bureau, QuickFacts, Housing Units, July 1, 2025 (V2025). Additional sources: U.S. Census Bureau, National, State, and County Housing Unit Totals: 2020-2025, May 2026; World Population Review, United States by Density 2026, for state area in square miles. Data accessed September 10, 2026.