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Single Family ResidenceResidential
$637,111
TopHap EstimateOur estimate of what this home would sell for today, based on nearby sales, the home's size and features, and local price trends. It is a starting point, not an appraisal.· confidence 88How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Sep 24, 2026
Last sold for $134,000 on Mar 31, 1999

21 40TH ST

ISLIP, NY 11751
0
Baths
0.35 ac
Lot SizeThe size of the land the home sits on, from county records.

Valuation

$637K
$560K low$714K high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$134,000 · Mar 31, 1999

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$12,147 (2024)
Assessed ValueThe value the county assigns to this home to calculate property tax. It is often lower than what the home would sell for.$41,500 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$8,800
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$32,700
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$584,507

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
CountySUFFOLK
Lot (acres)The size of the land the home sits on, from county records.0.35
PoolWhether the property has a pool, and what kind, such as in-ground.No

Assigned SchoolsThe public schools this address is zoned for. Boundaries change, so confirm with the district before you count on it.

E
Wing Elementary School
Elementary · Grades KG–1 · 1.0 mi
H
Islip High SchoolB
High · Grades 9–12 · 1.4 mi
M
Islip Middle SchoolB
Middle · Grades 7–8 · 1.6 mi

District: Islip Union Free School District

Neighborhood · ZIP 11751These are comparison scores, not percentages. 100 equals the national average, so 150 means about 50% above average.

CrimeLocal crime compared with the rest of the country, where 100 is average. It reflects things like population density, income, and how crime gets reported.59
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.102
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.69

Index scale: 100 = US average (tick). Lower is better.

Homes occupiedThe share of homes here that someone lives in. The rest sit empty, including vacation and for-sale homes.97%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.19%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.4.2%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.1%
PopulationHow many people live in this area.15,527
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.3,057 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$119,597
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$137,797
Average tempThe average temperature here across a full year.52°F
Annual precipHow much rain and melted snow falls here in a typical year.48 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.58%

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Data by ATTOM. Valuations are automated estimates, not appraisals. Photos from Google Street View and may not depict the current property state.

How this home compares

21 40th St measured against every home in its neighborhood, its ZIP code and its county, using county assessor records refreshed nightly. A home can stand out in one of those areas and look ordinary in another, because each one holds a different mix of homes.

  • Has a bigger lot than 73% of homes in Islip 11751

What homes are worth in Islip 11751

Each bar is how many homes fall in that price range. The marker is this home.

This home
$463K$1.8M

This home is worth more than 49% of homes in Islip 11751.

How it measures up in Islip 11751

The dot is this home. The mark in the middle is the typical home in Islip 11751.

Estimated value$637,111
CheaperTypical $640,729Pricier

Pricier than 49% of homes nearby

Lot size0.35 ac
SmallerTypical 0.24 acBigger

Bigger than 73% of homes nearby

How 21 40th St ranks against every home in each area.
MeasureThis homeIslipIslip 11751Suffolk County
Estimated valuepricier than$637,11152% of homes49% of homes38% of homes
Lot sizebigger than0.35 ac72% of homes73% of homes62% of homes

About 21 40th St

How much is 21 40th St, Islip, NY worth?

The TopHap Estimate for 21 40th St, Islip, NY is $637,111 as of Sep 24, 2026. The likely range is $560,357 to $713,865. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 21 40th St, Islip, NY last sell?

21 40th St, Islip, NY last sold on Mar 31, 1999 for $134,000, according to the county's recorded deed.

What schools serve 21 40th St, Islip, NY?

21 40th St, Islip, NY is assigned to Wing Elementary School (elementary); Islip High School (high), rated B; Islip Middle School (middle), rated B. All sit in Islip Union Free School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21 40th St, Islip, NY compare to other homes in Islip 11751?

Among the 4,170 homes in Islip 11751, it is worth more than 49% of them ($637,111 against a typical $640,729) and its lot is bigger than 73% of them (0.35 ac against a typical 0.24 ac). Measured against all of Suffolk County, it is worth more than 38% of homes there. These shares are recounted nightly from the full county assessor record for each area, not from active listings.

What are the property taxes on 21 40th St, Islip, NY?

The 2024 property tax bill for 21 40th St, Islip, NY was $12,147. The county assessed it at $41,500.

More homes on 40th St

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Assigned schools

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