Skip to content
Skip to content
TopHapOpen in map
Single Family ResidenceResidential
$3,942,723$999 / 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 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

646 ROUND HILL RD

GREENWICH, CT 06831
5
Beds
4
Baths
3,948 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 ac
Lot SizeThe size of the land the home sits on, from county records.
1983
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
9
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

$3.9M
$3.5M low$4.4M high

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$22,749 (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.$1,889,440 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$1,408,750
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$480,690
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$1,889,440
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$1,322,608

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.41
12
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
21
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.
95
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.
Projected Flood DepthHow deep a serious flood is expected to get here at some point in the next 30 years. Shown in inches.11 in
30-Year Flood ChanceThe chance of at least one serious flood here in the next 30 years, not in any single year.6%
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.4.00
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.Asphalt
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

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 · 1.3 mi
H
Greenwich High SchoolA+
High · Grades 9–12 · 6.7 mi
M
Western Middle SchoolA-
Middle · Grades 6–8 · 8.1 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%

Owner Tools

Do you own this home?
Claim this home

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

646 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.

  • Worth more than 95% of homes in Western Connecticut County
  • Costs more per square foot than 95% of homes in Western Connecticut County
  • Bigger than 88% of homes in Western Connecticut County
  • Has a bigger lot than 96% of homes in Western Connecticut County
  • Newer than 72% of homes in Western Connecticut County

What homes are worth in Greenwich 06831

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

This home
$674K$10M

This home is worth more than 70% 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.

Estimated value$3,942,723
CheaperTypical $2,179,708Pricier

Pricier than 70% of homes nearby

Price per ft²$999
CheaperTypical $706Pricier

Pricier than 88% of homes nearby

Living area3,948 ft²
SmallerTypical 2,979 ft²Bigger

Bigger than 64% of homes nearby

Lot size4 ac
SmallerTypical 1.38 acBigger

Bigger than 81% of homes nearby

Year built1983
OlderTypical 1968Newer

Newer than 71% of homes nearby

How 646 Round Hill Rd ranks against every home in each area.
MeasureThis homeGreenwich 06831Western Connecticut County
Estimated valuepricier than$3,942,72370% of homes95% of homes
Price per ft²pricier than$99988% of homes95% of homes
Living areabigger than3,948 ft²64% of homes88% of homes
Lot sizebigger than4 ac81% of homes96% of homes
Year builtnewer than198371% of homes72% of homes

About 646 Round Hill Rd

How much is 646 Round Hill Rd, Greenwich, CT worth?

The TopHap Estimate for 646 Round Hill Rd, Greenwich, CT is $3,942,723 as of Sep 24, 2026. The likely range is $3,470,179 to $4,415,267. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 646 Round Hill Rd, Greenwich, CT last sell?

646 Round Hill Rd, Greenwich, CT last sold on Jan 1, 1900, according to the county's recorded deed.

How big is 646 Round Hill Rd, Greenwich, CT?

646 Round Hill Rd, Greenwich, CT has 5 bedrooms, 4 bathrooms, 3,948 square feet of living space and a 4.00-acre lot.

When was 646 Round Hill Rd, Greenwich, CT built?

646 Round Hill Rd, Greenwich, CT was built in 1983, making it 43 years old. It is a colonial home. The building has 2 stories.

What schools serve 646 Round Hill Rd, Greenwich, CT?

646 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 646 Round Hill Rd, Greenwich, CT compare to other homes in Greenwich 06831?

Among the 5,196 homes in Greenwich 06831, it is worth more than 70% of them ($3,942,723 against a typical $2,179,708), its price per square foot is higher than 88% of them ($999 against a typical $706), it is bigger than 64% of them (3,948 ft² against a typical 2,979 ft²), its lot is bigger than 81% of them (4 ac against a typical 1.38 ac) and it is newer than 71% of them (1983 against a typical 1968). Measured against all of Western Connecticut County, it is worth more than 95% 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 646 Round Hill Rd, Greenwich, CT?

The 2025 property tax bill for 646 Round Hill Rd, Greenwich, CT was $22,749. The county assessed it at $1,889,440.

More homes on Round Hill Rd

Closest homes

More homes in Greenwich 06831

Assigned schools

Explore the area

See this home in context

Open 646 Round Hill Rd on TopHap’s interactive map to compare it against every sale nearby, overlay school zones and flood risk, and run a CMA.

Open in map
A flyover of TopHap's photorealistic 3D map, with recorded sale prices pinned to homes
Search any address, city, zip, or county…3D$1.9M$6.25MOpen in map