Islip, NY Profile: Facts & Data


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Islip, New York - Basic Facts

The Islip CDP(1) had a population of 18,363 as of July 1, 2021. Islip ranks in the upper quartile for Population Density and Diversity Index when compared to the other cities, towns and Census Designated Places (CDPs) in New York. See peer rankings below.

The primary coordinate point for Islip is located at latitude 40.7298 and longitude -73.2104 in Suffolk County. The formal boundaries for the Islip Census Designated Place encompass a land area of 4.82 sq. miles and a water area of 0.12 sq. miles. Suffolk County is in the Eastern time zone (GMT -5). The elevation is 13 feet.

The Islip Census Designated Place has a U1 Census Class Code which indicates a census designated place with an official federally recognized name. It also has a Functional Status Code of "S" which identifies a statistical entity.

The Islip Census Designated Place is located within Town of Islip, a minor civil division (MCD) of Suffolk County.

  1. A Census Designated Place (CDP) is a statistical counterpart to a self-governing (incorporated) place such as a city, town, or village. A CDP is not a legal entity and has no governmental functions.

Jump to... (On This Page!)
  1. Islip 2021 Demographic Data
  2. Growth Rates for Islip (Historical & 5-Year Forecast)
  3. Peer Comparisons (Rank and Percentile)
  1. Neighborhoods Demographics (Home Values, Household Income, etc.)
  2. New York Research Tools (Easy Tools & Current Data)
  3. New York Data Comparison Tool - 2021 Demographics

Islip, NY Data & Demographics (As of July 1, 2021)


Total Population 18,363 (100%)
Population in Households 18,305 (99.7%)
Population in Families 15,718 (85.6%)
Population in Group Quarters1 58 ( 0.3%)
Population Density 3,805
Diversity Index2 54


Median Household Income $112,977
Average Household Income $141,178
% of Income for Mortgage4 17%
Per Capita Income $48,949
Wealth Index5 194


Total HU (Housing Units) 6,701 (100%)
Owner Occupied HU 5,293 (79.0%)
Renter Occupied HU 1,073 (16.0%)
Vacant Housing Units 335 ( 5.0%)
Median Home Value $445,620
Average Home Value $519,370
Housing Affordability Index3 105


Total Households 6,366
Average Household Size 2.88
Family Households 4,684
Average Family Size 3
  1. Group Quarters - a place where people live or stay in a group living arrangement. Includes college residents halls, nursing facilities, military barracks, and correctional facilities.
  2. The Diversity Index is a scale of 0 to 100 that represents the likelihood that two persons, chosen at random from the same area, belong to different races or ethnic groups. If an area's entire population belongs to one race AND one ethnic group, then the area has zero diversity. An area's diversity index increases to 100 when the population is evenly divided into two or more race/ethnic groups.
  3. The Housing Affordability Index base is 100 and represents a balance point where a resident with a median household income can normally qualify to purchase a median price home. Values above 100 indicate increased affordability, while values below 100 indicate decreased affordability.
  4. The % of Income for Mortgage quantifies the percentage of median household income dedicated to mortgage payments on a home priced at the median value (assuming a 30-year mortgage and a 20% down payment).
  5. The Wealth Index is based on a number of indicators of affluence including average household income and average net worth, but it also includes the value of material possessions and resources. It represents the wealth of the area relative to the national level. Values above or below 100 represent above-average wealth or below-average wealth compared to the national level.


2010-2021 2021-2026
Population -0.16% -0.31%
Households -0.1% -0.32%
Families -0.21% -0.38%
Median Household Income   1.54%
Per Capita Income   2.02%
Owner Occupied HU   -0.14%

Islip, NY - Peer Comparisons by Rank and Percentile

The table below compares Islip to the other 1,195 incorporated cities, towns and CDPs in New York by rank and percentile using July 1, 2021 data. The location Ranked # 1 has the highest value. A location that ranks higher than 75% of its peers would be in the 75th percentile of the peer group.

Variable Description Rank Percentile
Total Population # 98 92nd
Population Density # 193 84th
Median Household Income # 229 81st
Housing Affordability Index # 333 28th
Per Capita Income # 295 75th
Diversity Index # 227 81st

Additional comparisons and rankings can be made with a VERY EASY TO USE New York Census Data Comparison Tool.

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