Southampton, East Hampton, and Shelter Island had the fastest percentage population growth among Long Island’s 13 civil towns between the Census Bureau’s April 1, 2020 estimates base and July 1, 2025. Brookhaven added the most residents over that period. For readers asking where new construction is most visible, communities such as Ronkonkoma, Yaphank, Farmingville, Patchogue, and Baldwin offer documented examples of housing development, but that does not make them the fastest-growing places by population.
Our Population & Demographics by Town page provides a broader overview of population, income, age, and education across Nassau County and Suffolk County. The growth comparison below uses a single Census population-estimates series so every town is measured over the same period.
Which Towns Grew Fastest by Population?
Southampton grew approximately 3.69%, narrowly ahead of East Hampton at 3.67%. Both round to 3.7% at one decimal place. Shelter Island followed at 3.49%, with Southold at 2.27% and Brookhaven at 2.22%. These are increases in estimated resident population, rather than seasonal visitors or the number of second homes.
Percentage growth and the number of people added answer different questions. Brookhaven increased by 10,779 residents, from an estimates base of 485,631 to a July 2025 estimate of 496,410. Southampton added 2,547 residents, while Shelter Island added 113. A small town can therefore rank highly by percentage without adding as many people as a much larger town.
Key Facts & Details
The table ranks all 13 civil towns by percentage change from April 1, 2020 to July 1, 2025. The starting figures are the Census Bureau’s revised 2020 estimates base, which can differ from the original 2020 Census count. Percentages are calculated from the published counts and shown to two decimal places.
| Civil Town | April 2020 Estimates Base | July 2025 Population Estimate | Population Change |
|---|---|---|---|
| Southampton | 69,054 | 71,601 | +3.69% |
| East Hampton | 28,359 | 29,400 | +3.67% |
| Shelter Island | 3,238 | 3,351 | +3.49% |
| Southold | 23,722 | 24,260 | +2.27% |
| Brookhaven | 485,631 | 496,410 | +2.22% |
| Riverhead | 35,964 | 36,394 | +1.20% |
| Huntington | 204,179 | 205,891 | +0.84% |
| Babylon | 218,177 | 219,766 | +0.73% |
| North Hempstead | 237,647 | 238,982 | +0.56% |
| Smithtown | 116,337 | 116,847 | +0.44% |
| Hempstead | 793,316 | 795,734 | +0.30% |
| Islip | 339,982 | 340,867 | +0.26% |
| Oyster Bay | 301,396 | 301,115 | -0.09% |
Source: U.S. Census Bureau, Vintage 2025 city and town population estimates. This comparison covers civil towns, not separate rankings of cities, incorporated villages, or hamlets. Census estimates may be revised in later releases.
Where Is New Housing Changing Communities?
Population rankings do not tell the whole development story. A project may add apartments, shops, and infrastructure to a small part of a town while other neighborhoods experience little change. Proposed or approved homes also should not be counted as completed homes or new residents.
Around the Ronkonkoma Long Island Rail Road station, Station Yards is being developed in phases. The state’s October 2024 announcement described an overall plan for 1,450 homes, alongside retail and office space. That figure describes the planned development, not a population increase or a claim that all units are complete.
In Yaphank, the Long Island Housing Partnership identifies The Brio at the Boulevard as a 295-unit rental complex. Its Arboretum at Farmingville listing describes a 292-unit complex in Farmingville. These are specific examples of housing added within the broader Town of Brookhaven.
In September 2025, New York State announced funding for several additional developments, including the 262-unit Carriage House project in Patchogue, the 215-unit Grand at Baldwin, and the 96-unit One Carleton Green project in Central Islip. The announcement documents planned housing investment; it does not establish how many residents had moved in by the population-estimate date.
Why Towns and Hamlets Need Separate Comparisons
A civil town is a municipal government that can contain many different communities. Riverhead can refer to the town or the hamlet, while Brentwood, Farmingville, and Yaphank are hamlets rather than separate town governments. A townwide increase cannot automatically be assigned to one neighborhood, and a large development in a hamlet does not establish its position in an island-wide population ranking.
For local context, start with our Population & Demographics by Town page and check the geography and year behind each figure. That page’s ACS demographic estimates serve a different purpose from the annual population-estimates series used here. Comparing overlapping five-year survey estimates as though they were individual annual counts can give a misleading impression of growth.
The clearest answer depends on the measure: Southampton, East Hampton, and Shelter Island led percentage growth among the 13 towns over the stated period, while Brookhaven added the most residents. New housing in places such as Ronkonkoma, Yaphank, Farmingville, Patchogue, and Baldwin illustrates a separate kind of change. Use population data to compare resident growth and project records to understand where construction and redevelopment are occurring.