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Single Family ResidenceResidential
$604,250$320 / 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 92How 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

21 PROSPECT AVE

CHELSEA, MA 02150
4
Beds
2
Baths
1,888 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.
3,440 ft²
Lot SizeThe size of the land the home sits on, from county records.
1940
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
8
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.
4
ParkingThe number of parking spaces on the property, including the garage.

Valuation

$604K
$557K low$651K high

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$6,638 (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.$578,200 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$197,700
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$380,500
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$568,700
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$679,345

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
CountySUFFOLK
Lot (acres)The size of the land the home sits on, from county records.0.08
HeatingThe type of heating system in the home.Hot Water
PoolWhether the property has a pool, and what kind, such as in-ground.No

Assigned SchoolsThe public schools this address is zoned for. Boundaries change, so confirm with the district before you count on it.

H
Chelsea High SchoolD-
High · Grades 9–12 · 0.9 mi
M
Clark Avenue SchoolF
Middle · Grades 5–8 · 1.0 mi
E
William a Berkowitz Elementary SchoolC+
Elementary · Grades 1–4 · 1.0 mi

District: Chelsea School District

Neighborhood · ZIP 02150These 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.89
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.105
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.76

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.17%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.16%
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.40,106
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.16,087 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$72,192
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$94,537
Average tempThe average temperature here across a full year.50°F
Annual precipHow much rain and melted snow falls here in a typical year.45 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

21 Prospect Ave 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 79% of homes in Chelsea 02150
  • Costs less per square foot than 96% of homes in Suffolk County
  • Newer than 69% of homes in Chelsea 02150

What homes are worth in Chelsea 02150

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

This home
$279K$830K

This home is worth more than 79% of homes in Chelsea 02150.

How it measures up in Chelsea 02150

The dot is this home. The mark in the middle is the typical home in Chelsea 02150.

Estimated value$604,250
CheaperTypical $491,046Pricier

Pricier than 79% of homes nearby

Price per ft²$320
CheaperTypical $437Pricier

Pricier than 7% of homes nearby

Living area1,888 ft²
SmallerTypical 1,726 ft²Bigger

Bigger than 54% of homes nearby

Lot size3,440 ft²
SmallerTypical 3,703 ft²Bigger

Bigger than 44% of homes nearby

Year built1940
OlderTypical 1920Newer

Newer than 69% of homes nearby

How 21 Prospect Ave ranks against every home in each area.
MeasureThis homeChelsea 02150Suffolk County
Estimated valuepricier than$604,25079% of homes34% of homes
Price per ft²pricier than$3207% of homes4% of homes
Living areabigger than1,888 ft²54% of homes64% of homes
Lot sizebigger than3,440 ft²44% of homes57% of homes
Year builtnewer than194069% of homes66% of homes

About 21 Prospect Ave

How much is 21 Prospect Ave, Chelsea, MA worth?

The TopHap Estimate for 21 Prospect Ave, Chelsea, MA is $604,250 as of Sep 24, 2026. The likely range is $557,143 to $651,357. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 21 Prospect Ave, Chelsea, MA last sell?

21 Prospect Ave, Chelsea, MA last sold on Jan 1, 1900, according to the county's recorded deed.

How big is 21 Prospect Ave, Chelsea, MA?

21 Prospect Ave, Chelsea, MA has 4 bedrooms, 2 bathrooms, 1,888 square feet of living space and a 0.08-acre lot.

When was 21 Prospect Ave, Chelsea, MA built?

21 Prospect Ave, Chelsea, MA was built in 1940, making it 86 years old. It is a conventional home. The building has 2 stories.

What schools serve 21 Prospect Ave, Chelsea, MA?

21 Prospect Ave, Chelsea, MA is assigned to Chelsea High School (high), rated D-; Clark Avenue School (middle), rated F; William a Berkowitz Elementary School (elementary), rated C+. All sit in Chelsea School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21 Prospect Ave, Chelsea, MA compare to other homes in Chelsea 02150?

Among the 5,340 homes in Chelsea 02150, it is worth more than 79% of them ($604,250 against a typical $491,046), its price per square foot is higher than 7% of them ($320 against a typical $437), it is bigger than 54% of them (1,888 ft² against a typical 1,726 ft²), its lot is bigger than 44% of them (3,440 ft² against a typical 3,703 ft²) and it is newer than 69% of them (1940 against a typical 1920). Measured against all of Suffolk County, it is worth more than 34% 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 Prospect Ave, Chelsea, MA?

The 2026 property tax bill for 21 Prospect Ave, Chelsea, MA was $6,638. The county assessed it at $578,200.

More homes on Prospect Ave

Closest homes

More homes in Chelsea 02150

Assigned schools

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