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Single Family ResidenceResidential
$802,675$291 / 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 94How 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 $80,000 on Aug 3, 2015

21 UNION ST

BLACKSTONE, MA 01504
4
Beds
3.5
Baths
2,756 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.
2.75 ac
Lot SizeThe size of the land the home sits on, from county records.
2020
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.

Valuation

$803K
$751K low$854K high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$80,000 · Aug 3, 2015

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$10,657 (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.$723,000 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$186,000
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$537,000
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$651,200
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$741,760

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
CountyWORCESTER
Lot (acres)The size of the land the home sits on, from county records.2.75
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
PoolWhether the property has a pool, and what kind, such as in-ground.No

Transaction History(2)

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
John F. Kennedy Elementary SchoolB+
Elementary · Grades KG–2 · 1.8 mi
H
Blackstone - Millville Regional High SchoolC-
High · Grades 9–12 · 1.9 mi
M
Frederick W. Hartnett Middle SchoolC
Middle · Grades 6–8 · 2.6 mi

District: Blackstone-Millville School District

Neighborhood · ZIP 01504These 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.93
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.100
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.57

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.95%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.23%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.5.4%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.3%
PopulationHow many people live in this area.9,321
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.819 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$97,474
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$118,407
Average tempThe average temperature here across a full year.49°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.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 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.

  • Among the most valuable homes in Blackstone 01504
  • Bigger than 91% of homes in Blackstone 01504
  • Has a bigger lot than 89% of homes in Blackstone 01504
  • Among the newest homes in Blackstone 01504

What homes are worth in Blackstone 01504

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

This home
$267K$780K

This home is worth more than almost all homes in Blackstone 01504.

How it measures up in Blackstone 01504

The dot is this home. The mark in the middle is the typical home in Blackstone 01504.

Estimated value$802,675
CheaperTypical $440,394Pricier

Pricier than almost all homes nearby

Price per ft²$291
CheaperTypical $302Pricier

Pricier than 41% of homes nearby

Living area2,756 ft²
SmallerTypical 1,584 ft²Bigger

Bigger than 91% of homes nearby

Lot size2.75 ac
SmallerTypical 0.56 acBigger

Bigger than 89% of homes nearby

Year built2020
OlderTypical 1976Newer

Newer than almost all homes nearby

How 21 Union St ranks against every home in each area.
MeasureThis homeBlackstone 01504Worcester County
Estimated valuepricier than$802,675almost all homes90% of homes
Price per ft²pricier than$29141% of homes42% of homes
Living areabigger than2,756 ft²91% of homes85% of homes
Lot sizebigger than2.75 ac89% of homes87% of homes
Year builtnewer than2020almost all homes98% of homes

About 21 Union St

How much is 21 Union St, Blackstone, MA worth?

The TopHap Estimate for 21 Union St, Blackstone, MA is $802,675 as of Sep 24, 2026. The likely range is $751,261 to $854,089. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 21 Union St, Blackstone, MA last sell?

21 Union St, Blackstone, MA last sold on Aug 3, 2015 for $80,000, according to the county's recorded deed.

How big is 21 Union St, Blackstone, MA?

21 Union St, Blackstone, MA has 4 bedrooms, 3.5 bathrooms, 2,756 square feet of living space and a 2.75-acre lot.

When was 21 Union St, Blackstone, MA built?

21 Union St, Blackstone, MA was built in 2020, making it 6 years old. It is a colonial home. The building has 2 stories.

What schools serve 21 Union St, Blackstone, MA?

21 Union St, Blackstone, MA is assigned to John F. Kennedy Elementary School (elementary), rated B+; Blackstone - Millville Regional High School (high), rated C-; Frederick W. Hartnett Middle School (middle), rated C. All sit in Blackstone-Millville School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21 Union St, Blackstone, MA compare to other homes in Blackstone 01504?

Among the 2,985 homes in Blackstone 01504, it is worth more than almost all of them ($802,675 against a typical $440,394), its price per square foot is higher than 41% of them ($291 against a typical $302), it is bigger than 91% of them (2,756 ft² against a typical 1,584 ft²), its lot is bigger than 89% of them (2.75 ac against a typical 0.56 ac) and it is newer than almost all of them (2020 against a typical 1976). Measured against all of Worcester County, it is worth more than 90% 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 Union St, Blackstone, MA?

The 2026 property tax bill for 21 Union St, Blackstone, MA was $10,657. The county assessed it at $723,000.

More homes on Union St

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Assigned schools

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