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Single Family ResidenceResidential
$515,857$416 / 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 Aug 30, 2026

173 UNION ST

HOLLISTON, MA 01746
3
Beds
1.5
Baths
1,241 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.
4.38 ac
Lot SizeThe size of the land the home sits on, from county records.
1871
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
6
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.

Valuation

$516K
$495K low$536K high

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$7,757 (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.$529,500 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$277,300
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$252,200
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$547,390

Climate Risk

Projected Flood DepthHow deep a serious flood is expected to get here at some point in the next 30 years. Shown in inches.124 in
30-Year Flood ChanceThe chance of at least one serious flood here in the next 30 years, not in any single year.51%
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.1 percent flood zone

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.Conventional
CountyMIDDLESEX
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.1988
Lot (acres)The size of the land the home sits on, from county records.4.38
ConstructionThe main material the home's frame and walls are built from.Stone
RoofThe main material covering the roof, such as asphalt shingle or tile.Asphalt
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, Detached
PoolWhether the property has a pool, and what kind, such as in-ground.No

Transaction History(7)

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
Robert H. Adams Middle SchoolA-
Middle · Grades 6–8 · 0.9 mi
H
Holliston High SchoolA
High · Grades 9–12 · 1.0 mi
E
Placentino Elementary School
Elementary · Grades PK–2 · 1.1 mi

District: Holliston School District

Neighborhood · ZIP 01746These 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.11
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.93
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.67

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.39%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.3.1%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.4%
PopulationHow many people live in this area.15,460
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.813 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$148,945
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$184,552
Average tempThe average temperature here across a full year.49°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

173 Union 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.

  • Worth less than 89% of homes in Holliston 01746
  • Smaller than 78% of homes in Holliston 01746
  • Has a bigger lot than 94% of homes in Middlesex County
  • Older than 98% of homes in Middlesex County

What homes are worth in Holliston 01746

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

This home
$225K$1.5M

This home is worth more than 11% of homes in Holliston 01746.

How it measures up in Holliston 01746

The dot is this home. The mark in the middle is the typical home in Holliston 01746.

Estimated value$515,857
CheaperTypical $723,980Pricier

Pricier than 11% of homes nearby

Price per ft²$416
CheaperTypical $390Pricier

Pricier than 62% of homes nearby

Living area1,241 ft²
SmallerTypical 1,896 ft²Bigger

Bigger than 22% of homes nearby

Lot size4.38 ac
SmallerTypical 0.69 acBigger

Bigger than 91% of homes nearby

Year built1871
OlderTypical 1968Newer

Newer than 5% of homes nearby

How 173 Union St ranks against every home in each area.
MeasureThis homeHolliston 01746Middlesex County
Estimated valuepricier than$515,85711% of homes16% of homes
Price per ft²pricier than$41662% of homes37% of homes
Living areabigger than1,241 ft²22% of homes22% of homes
Lot sizebigger than4.38 ac91% of homes94% of homes
Year builtnewer than18715% of homes2% of homes

About 173 Union St

How much is 173 Union St, Holliston, MA worth?

The TopHap Estimate for 173 Union St, Holliston, MA is $515,857 as of Aug 30, 2026. The likely range is $495,313 to $536,401. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 173 Union St, Holliston, MA last sell?

173 Union St, Holliston, MA last sold on Dec 14, 2004, according to the county's recorded deed. TopHap holds 2 recorded sales for this parcel.

How big is 173 Union St, Holliston, MA?

173 Union St, Holliston, MA has 3 bedrooms, 1.5 bathrooms, 1,241 square feet of living space and a 4.38-acre lot.

When was 173 Union St, Holliston, MA built?

173 Union St, Holliston, MA was built in 1871, making it 155 years old. It is a conventional home. The building has 2 stories.

What schools serve 173 Union St, Holliston, MA?

173 Union St, Holliston, MA is assigned to Robert H. Adams Middle School (middle), rated A-; Holliston High School (high), rated A; Placentino Elementary School (elementary). All sit in Holliston School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 173 Union St, Holliston, MA compare to other homes in Holliston 01746?

Among the 5,229 homes in Holliston 01746, it is worth more than 11% of them ($515,857 against a typical $723,980), its price per square foot is higher than 62% of them ($416 against a typical $390), it is bigger than 22% of them (1,241 ft² against a typical 1,896 ft²), its lot is bigger than 91% of them (4.38 ac against a typical 0.69 ac) and it is newer than 5% of them (1871 against a typical 1968). Measured against all of Middlesex County, it is worth more than 16% 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 173 Union St, Holliston, MA?

The 2025 property tax bill for 173 Union St, Holliston, MA was $7,757. The county assessed it at $529,500.

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