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Single Family ResidenceResidential
$5,086,978$888 / ft²
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 92How 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 $2,475,000 on Dec 27, 2018

21 KNOLLWOOD DR

GREENWICH, CT 06830
6
Beds
5 / 2
Baths
5,731 ft²
Living AreaTotal finished area of the structures, from county records. Some counties include shared space like hallways or a building gym, so it may not match a listing.
2.38 ac
Lot SizeThe size of the land the home sits on, from county records.
1981
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
15
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.
1
ParkingThe number of parking spaces on the property, including the garage.

Valuation

$5.1M
$4.7M low$5.5M high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$2,475,000 · Dec 27, 2018

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$33,560 (2026)
Assessed ValueThe value the county assigns to this home to calculate property tax. It is often lower than what the home would sell for.$3,201,030 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$1,178,660
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$2,022,370
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$2,238,250
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$5,050,294

Climate Risk

Overall riskThe average of the five hazard scores below, on a 0 to 100 scale. Higher means greater projected risk over the coming decades.49
21
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
22
WildfireProjected wildfire risk, scored 0 to 100, based on how much land burns in a typical year. Higher is riskier.
65
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
96
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
43
DroughtProjected water shortage risk, scored 0 to 100. Higher means more strain on the local water supply.
Projected Flood DepthHow deep a serious flood is expected to get here at some point in the next 30 years. Shown in inches.3 in
30-Year Flood ChanceThe chance of at least one serious flood here in the next 30 years, not in any single year.30%
FEMA Flood ZoneFEMA's flood zone for this address. Zones starting with A or V are high risk, and lenders usually require flood insurance there.minimal

Scores 0–100; higher = greater projected risk.

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
StyleThe architectural style of the home, such as ranch or colonial.Colonial
CountyWESTERN CONNECTICUT
Effective Year BuiltAn adjusted build year that accounts for condition and major remodels. A big renovation can make a home count as newer than it is.1985
Lot (acres)The size of the land the home sits on, from county records.2.38
ConstructionThe main material the home's frame and walls are built from.Frame (Unspecified)
RoofThe main material covering the roof, such as asphalt shingle or tile.Wood Shingle
HeatingThe type of heating system in the home.Forced Air With Air Conditioning
CoolingThe type of cooling or air conditioning in the home.Yes
FireplaceWhether the home has a fireplace, and what kind.Yes
GarageWhether the property has a garage, and details like whether it is attached to the home.Garage, Attached
PoolWhether the property has a pool, and what kind, such as in-ground.No
FeaturesExtra features found in county records. Records are not complete everywhere, so a missing feature does not always mean the home lacks it.Greenhouse

Transaction History(3)

Sales and refinances filed with the county for this home. Not every transfer is a normal sale, so check the type before comparing prices.

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

E
North Street SchoolA+
Elementary · Grades PK–5 · 0.6 mi
H
Greenwich High SchoolA+
High · Grades 9–12 · 1.0 mi
M
Central Middle SchoolA
Middle · Grades 6–8 · 1.1 mi

District: Greenwich School District

Neighborhood · ZIP 06830These 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.110
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.119
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.104

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.90%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.30%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.7.6%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.0.8%
PopulationHow many people live in this area.27,704
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.1,501 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$168,325
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$273,728
Average tempThe average temperature here across a full year.52°F
Annual precipHow much rain and melted snow falls here in a typical year.50 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 Knollwood Dr 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.

  • Worth more than 98% of homes in Western Connecticut County
  • Costs more per square foot than 92% of homes in Western Connecticut County
  • Bigger than 96% of homes in Western Connecticut County
  • Has a bigger lot than 91% of homes in Greenwich 06830
  • Newer than 72% of homes in Greenwich 06830

What homes are worth in Greenwich 06830

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

This home
$673K$10M

This home is worth more than 75% of homes in Greenwich 06830.

How it measures up in Greenwich 06830

The dot is this home. The mark in the middle is the typical home in Greenwich 06830.

Estimated value$5,086,978
CheaperTypical $3,032,995Pricier

Pricier than 75% of homes nearby

Price per ft²$888
CheaperTypical $924Pricier

Pricier than 44% of homes nearby

Living area5,731 ft²
SmallerTypical 2,947 ft²Bigger

Bigger than 82% of homes nearby

Lot size2.38 ac
SmallerTypical 0.46 acBigger

Bigger than 91% of homes nearby

Year built1981
OlderTypical 1956Newer

Newer than 72% of homes nearby

How 21 Knollwood Dr ranks against every home in each area.
MeasureThis homeGreenwich 06830Western Connecticut County
Estimated valuepricier than$5,086,97875% of homes98% of homes
Price per ft²pricier than$88844% of homes92% of homes
Living areabigger than5,731 ft²82% of homes96% of homes
Lot sizebigger than2.38 ac91% of homes90% of homes
Year builtnewer than198172% of homes70% of homes

About 21 Knollwood Dr

How much is 21 Knollwood Dr, Greenwich, CT worth?

The TopHap Estimate for 21 Knollwood Dr, Greenwich, CT is $5,086,978 as of Sep 24, 2026. The likely range is $4,693,684 to $5,480,272. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 21 Knollwood Dr, Greenwich, CT last sell?

21 Knollwood Dr, Greenwich, CT last sold on Dec 27, 2018 for $2,475,000, according to the county's recorded deed. TopHap holds 2 recorded sales for this parcel.

How big is 21 Knollwood Dr, Greenwich, CT?

21 Knollwood Dr, Greenwich, CT has 6 bedrooms, 5 bathrooms, 5,731 square feet of living space and a 2.38-acre lot.

When was 21 Knollwood Dr, Greenwich, CT built?

21 Knollwood Dr, Greenwich, CT was built in 1981, making it 45 years old. It is a colonial home. The building has 2 stories.

What schools serve 21 Knollwood Dr, Greenwich, CT?

21 Knollwood Dr, Greenwich, CT is assigned to North Street School (elementary), rated A+; Greenwich High School (high), rated A+; Central Middle School (middle), rated A. All sit in Greenwich School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21 Knollwood Dr, Greenwich, CT compare to other homes in Greenwich 06830?

Among the 6,738 homes in Greenwich 06830, it is worth more than 75% of them ($5,086,978 against a typical $3,032,995), its price per square foot is higher than 44% of them ($888 against a typical $924), it is bigger than 82% of them (5,731 ft² against a typical 2,947 ft²), its lot is bigger than 91% of them (2.38 ac against a typical 0.46 ac) and it is newer than 72% of them (1981 against a typical 1956). Measured against all of Western Connecticut County, it is worth more than 98% 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 Knollwood Dr, Greenwich, CT?

The 2026 property tax bill for 21 Knollwood Dr, Greenwich, CT was $33,560. The county assessed it at $3,201,030.

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