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Single Family ResidenceResidential
$871,890$319 / 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 96How 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 $445,000 on Jun 29, 2012

21 FLAGG RD

SOUTHBOROUGH, MA 01772
3
Beds
2.5
Baths
2,730 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.
1.5 ac
Lot SizeThe size of the land the home sits on, from county records.
1840
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
7
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.

Valuation

$872K
$835K low$909K high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$445,000 · Jun 29, 2012

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$11,497 (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.$832,500 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$307,600
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$524,900
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$789,600
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$949,715

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
CountyWORCESTER
Lot (acres)The size of the land the home sits on, from county records.1.50
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
FireplaceWhether the home has a fireplace, and what kind.Yes
PoolWhether the property has a pool, and what kind, such as in-ground.No

Transaction History(6)

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.

M
P Brent TrottierA-
Middle · Grades 6–8 · 0.3 mi
E
Mary E Finn School
Elementary · Grades PK–1 · 1.7 mi
H
Algonquin Regional High SchoolA
High · Grades 9–12 · 3.9 mi

District: Southborough School District

Neighborhood · ZIP 01772These 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.32
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.103
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.63

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.32%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.3.7%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.5%
PopulationHow many people live in this area.10,867
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.705 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$180,666
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$225,158
Average tempThe average temperature here across a full year.48°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.50%

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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 Flagg 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 93% of homes in Worcester County
  • Costs less per square foot than 92% of homes in Southborough 01772
  • Bigger than 85% of homes in Worcester County
  • Has a bigger lot than 78% of homes in Worcester County
  • Among the oldest homes in Southborough 01772

What homes are worth in Southborough 01772

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

This home
$493K$2.2M

This home is worth more than 39% of homes in Southborough 01772.

How it measures up in Southborough 01772

The dot is this home. The mark in the middle is the typical home in Southborough 01772.

Estimated value$871,890
CheaperTypical $951,262Pricier

Pricier than 39% of homes nearby

Price per ft²$319
CheaperTypical $412Pricier

Pricier than 8% of homes nearby

Living area2,730 ft²
SmallerTypical 2,454 ft²Bigger

Bigger than 61% of homes nearby

Lot size1.5 ac
SmallerTypical 1 acBigger

Bigger than 76% of homes nearby

Year built1840
OlderTypical 1984Newer

Older than almost all homes nearby

How 21 Flagg Rd ranks against every home in each area.
MeasureThis homeSouthborough 01772Worcester County
Estimated valuepricier than$871,89039% of homes93% of homes
Price per ft²pricier than$3198% of homes57% of homes
Living areabigger than2,730 ft²61% of homes85% of homes
Lot sizebigger than1.5 ac76% of homes78% of homes
Year builtnewer than1840almost no homes2% of homes

About 21 Flagg Rd

How much is 21 Flagg Rd, Southborough, MA worth?

The TopHap Estimate for 21 Flagg Rd, Southborough, MA is $871,890 as of Sep 24, 2026. The likely range is $834,832 to $908,948. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 21 Flagg Rd, Southborough, MA last sell?

21 Flagg Rd, Southborough, MA last sold on Jun 29, 2012 for $445,000, according to the county's recorded deed. TopHap holds 2 recorded sales for this parcel.

How big is 21 Flagg Rd, Southborough, MA?

21 Flagg Rd, Southborough, MA has 3 bedrooms, 2.5 bathrooms, 2,730 square feet of living space and a 1.50-acre lot.

When was 21 Flagg Rd, Southborough, MA built?

21 Flagg Rd, Southborough, MA was built in 1840, making it 186 years old. The building has 2 stories.

What schools serve 21 Flagg Rd, Southborough, MA?

21 Flagg Rd, Southborough, MA is assigned to P Brent Trottier (middle), rated A-; Mary E Finn School (elementary); Algonquin Regional High School (high), rated A. All sit in Southborough School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21 Flagg Rd, Southborough, MA compare to other homes in Southborough 01772?

Among the 3,253 homes in Southborough 01772, it is worth more than 39% of them ($871,890 against a typical $951,262), its price per square foot is higher than 8% of them ($319 against a typical $412), it is bigger than 61% of them (2,730 ft² against a typical 2,454 ft²), its lot is bigger than 76% of them (1.5 ac against a typical 1 ac) and it is newer than almost none of them (1840 against a typical 1984). Measured against all of Worcester County, it is worth more than 93% 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 Flagg Rd, Southborough, MA?

The 2025 property tax bill for 21 Flagg Rd, Southborough, MA was $11,497. The county assessed it at $832,500.

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