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Duplex (2 Units, Any Combination)Residential
Last sold for $14,685,000 on Nov 4, 2020

521 ROUND HILL RD

GREENWICH, CT 06831
4
Beds
2.5
Baths
2,090 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.
4.54 ac
Lot SizeThe size of the land the home sits on, from county records.
1916
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
10
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

Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$14,685,000 · Nov 4, 2020

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$24,537 (2025)
Assessed ValueThe value the county assigns to this home to calculate property tax. It is often lower than what the home would sell for.$2,037,980 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$1,495,690
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$542,290
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$2,037,980
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$1,426,586

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.40
1
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
26
WildfireProjected wildfire risk, scored 0 to 100, based on how much land burns in a typical year. Higher is riskier.
64
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
94
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
16
DroughtProjected water shortage risk, scored 0 to 100. Higher means more strain on the local water supply.
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.Duplex (2 Units, Any Combination)
StyleThe architectural style of the home, such as ranch or colonial.Duplex Single
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.1970
Lot (acres)The size of the land the home sits on, from county records.4.54
ConstructionThe main material the home's frame and walls are built from.Brick
RoofThe main material covering the roof, such as asphalt shingle or tile.Wood Shingle
HeatingThe type of heating system in the home.Hot Water
CoolingThe type of cooling or air conditioning in the home.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.Deck

Transaction History(1)

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
Parkway SchoolA+
Elementary · Grades KG–5 · 0.7 mi
H
Greenwich High SchoolA+
High · Grades 9–12 · 5.8 mi
M
Western Middle SchoolA
Middle · Grades 6–8 · 7.2 mi

District: Greenwich School District

Neighborhood · ZIP 06831These 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.76
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.112
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.105

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.89%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.35%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.5.0%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.0.9%
PopulationHow many people live in this area.17,909
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.648 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$210,519
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$312,404
Average tempThe average temperature here across a full year.52°F
Annual precipHow much rain and melted snow falls here in a typical year.51 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

521 Round Hill Rd 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.

  • Smaller than 72% of homes in Greenwich 06831
  • Has a bigger lot than 97% of homes in Western Connecticut County
  • Older than 94% of homes in Greenwich 06831

How it measures up in Greenwich 06831

The dot is this home. The mark in the middle is the typical home in Greenwich 06831.

Living area2,090 ft²
SmallerTypical 2,968 ft²Bigger

Bigger than 28% of homes nearby

Lot size4.54 ac
SmallerTypical 1.41 acBigger

Bigger than 89% of homes nearby

Year built1916
OlderTypical 1968Newer

Newer than 6% of homes nearby

How 521 Round Hill Rd ranks against every home in each area.
MeasureThis homeGreenwich 06831Western Connecticut County
Living areabigger than2,090 ft²28% of homes54% of homes
Lot sizebigger than4.54 ac89% of homes97% of homes
Year builtnewer than19166% of homes7% of homes

About 521 Round Hill Rd

When did 521 Round Hill Rd, Greenwich, CT last sell?

521 Round Hill Rd, Greenwich, CT last sold on Nov 4, 2020 for $14,685,000, according to the county's recorded deed.

How big is 521 Round Hill Rd, Greenwich, CT?

521 Round Hill Rd, Greenwich, CT has 4 bedrooms, 2.5 bathrooms, 2,090 square feet of living space and a 4.54-acre lot.

When was 521 Round Hill Rd, Greenwich, CT built?

521 Round Hill Rd, Greenwich, CT was built in 1916, making it 110 years old. It is a duplex single home. The building has 2 stories.

What schools serve 521 Round Hill Rd, Greenwich, CT?

521 Round Hill Rd, Greenwich, CT is assigned to Parkway School (elementary), rated A+; Greenwich High School (high), rated A+; Western 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 521 Round Hill Rd, Greenwich, CT compare to other homes in Greenwich 06831?

Among the 5,196 homes in Greenwich 06831, it is bigger than 28% of them (2,090 ft² against a typical 2,968 ft²), its lot is bigger than 89% of them (4.54 ac against a typical 1.41 ac) and it is newer than 6% of them (1916 against a typical 1968). These shares are recounted nightly from the full county assessor record for each area, not from active listings.

What are the property taxes on 521 Round Hill Rd, Greenwich, CT?

The 2025 property tax bill for 521 Round Hill Rd, Greenwich, CT was $24,537. The county assessed it at $2,037,980.

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