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Duplex (2 Units, Any Combination)Residential
Last sold for $185,000 on Dec 1, 1999

21 RIVER ST

BILLERICA, MA 01821
4
Beds
2
Baths
2,524 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.
0.24 ac
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.
9
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.

Valuation

Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$185,000 · Dec 1, 1999

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$6,265 (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.$551,000 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$263,900
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$287,100
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$490,300

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Duplex (2 Units, Any Combination)
CountyMiddlesex
Lot (acres)The size of the land the home sits on, from county records.0.24
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.Hot Water
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.

H
Billerica Memorial High SchoolC
High · Grades 8–12 · 0.1 mi
E
ParkerA-
Elementary · Grades KG–4 · 0.1 mi
M
Marshall Middle SchoolB-
Middle · Grades 5–7 · 0.7 mi

District: Billerica School District

Neighborhood · ZIP 01821These 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.40
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 100.82

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.98%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.28%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.3.8%
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.31,495
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.1,857 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$133,460
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$152,991
Average tempThe average temperature here across a full year.49°F
Annual precipHow much rain and melted snow falls here in a typical year.47 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 River 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.

  • Bigger than 81% of homes in Billerica 01821
  • Has a smaller lot than 79% of homes in Billerica 01821
  • Older than 88% of homes in Billerica 01821

How it measures up in Billerica 01821

The dot is this home. The mark in the middle is the typical home in Billerica 01821.

Living area2,524 ft²
SmallerTypical 1,872 ft²Bigger

Bigger than 81% of homes nearby

Lot size0.24 ac
SmallerTypical 0.56 acBigger

Bigger than 21% of homes nearby

Year built1940
OlderTypical 1970Newer

Newer than 12% of homes nearby

How 21 River St ranks against every home in each area.
MeasureThis homeBillerica 01821Middlesex County
Living areabigger than2,524 ft²81% of homes74% of homes
Lot sizebigger than0.24 ac21% of homes42% of homes
Year builtnewer than194012% of homes36% of homes

About 21 River St

When did 21 River St, Billerica, MA last sell?

21 River St, Billerica, MA last sold on Dec 1, 1999 for $185,000, according to the county's recorded deed. TopHap holds 3 recorded sales for this parcel.

How big is 21 River St, Billerica, MA?

21 River St, Billerica, MA has 4 bedrooms, 2 bathrooms, 2,524 square feet of living space and a 0.24-acre lot.

When was 21 River St, Billerica, MA built?

21 River St, Billerica, MA was built in 1940, making it 86 years old. The building has 2 stories.

What schools serve 21 River St, Billerica, MA?

21 River St, Billerica, MA is assigned to Billerica Memorial High School (high), rated C; Parker (elementary), rated A-; Marshall Middle School (middle), rated B-. All sit in Billerica School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21 River St, Billerica, MA compare to other homes in Billerica 01821?

Among the 10,003 homes in Billerica 01821, it is bigger than 81% of them (2,524 ft² against a typical 1,872 ft²), its lot is bigger than 21% of them (0.24 ac against a typical 0.56 ac) and it is newer than 12% of them (1940 against a typical 1970). 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 River St, Billerica, MA?

The 2025 property tax bill for 21 River St, Billerica, MA was $6,265. The county assessed it at $551,000.

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