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Duplex (2 Units, Any Combination)Residential
Last sold for $3,950,000 on Nov 17, 2023

20 MONUMENT SQ

CHARLESTOWN, MA 02129
5
Beds
6 / 2
Baths
5,791 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.
2,500 ft²
Lot SizeThe size of the land the home sits on, from county records.
1870
Year BuiltThe year the home was originally built, according to county records.
4
StoriesHow many floors the home has above ground.
15
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.
2
ParkingThe number of parking spaces on the property, including the garage.

Valuation

Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$3,950,000 · Nov 17, 2023

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$44,024 (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.$3,801,700 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$1,092,600
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$2,709,100

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Duplex (2 Units, Any Combination)
CountySUFFOLK
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.2001
Lot (acres)The size of the land the home sits on, from county records.0.06
RoofThe main material covering the roof, such as asphalt shingle or tile.Slate
HeatingThe type of heating system in the home.Forced Air With Air Conditioning
CoolingThe type of cooling or air conditioning in the home.Yes
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(8)

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
Harvard / Kent Elementary SchoolC-
Elementary · Grades PK–5 · 0.1 mi
H
Charlestown High SchoolD+
High · Grades 9–12 · 0.2 mi
M
Warren / Prescott K-8 SchoolA-
Middle · Grades PK–8 · 0.2 mi

District: Boston School District

Neighborhood · ZIP 02129These 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.101
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.73

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.94%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.35%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.8.3%
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.18,397
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.10,594 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$152,177
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$178,903
Average tempThe average temperature here across a full year.50°F
Annual precipHow much rain and melted snow falls here in a typical year.46 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

20 Monument Sq 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 largest homes in Charlestown 02129
  • Has a bigger lot than 93% of homes in Charlestown 02129
  • Older than 97% of homes in Suffolk County

How it measures up in Charlestown 02129

The dot is this home. The mark in the middle is the typical home in Charlestown 02129.

Living area5,791 ft²
SmallerTypical 1,204 ft²Bigger

Bigger than almost all homes nearby

Lot size2,500 ft²
SmallerTypical 1,089 ft²Bigger

Bigger than 93% of homes nearby

Year built1870
OlderTypical 1899Newer

Newer than 18% of homes nearby

How 20 Monument Sq ranks against every home in each area.
MeasureThis homeCharlestown 02129Suffolk County
Living areabigger than5,791 ft²almost all homesalmost all homes
Lot sizebigger than2,500 ft²93% of homes50% of homes
Year builtnewer than187018% of homes3% of homes

About 20 Monument Sq

When did 20 Monument Sq, Charlestown, MA last sell?

20 Monument Sq, Charlestown, MA last sold on Nov 17, 2023 for $3,950,000, according to the county's recorded deed. TopHap holds 2 recorded sales for this parcel.

How big is 20 Monument Sq, Charlestown, MA?

20 Monument Sq, Charlestown, MA has 5 bedrooms, 6 bathrooms, 5,791 square feet of living space and a 0.06-acre lot.

When was 20 Monument Sq, Charlestown, MA built?

20 Monument Sq, Charlestown, MA was built in 1870, making it 156 years old. The building has 4 stories.

What schools serve 20 Monument Sq, Charlestown, MA?

20 Monument Sq, Charlestown, MA is assigned to Harvard / Kent Elementary School (elementary), rated C-; Charlestown High School (high), rated D+; Warren / Prescott K-8 School (middle), rated A-. All sit in Boston School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 20 Monument Sq, Charlestown, MA compare to other homes in Charlestown 02129?

Among the 5,261 homes in Charlestown 02129, it is bigger than almost all of them (5,791 ft² against a typical 1,204 ft²), its lot is bigger than 93% of them (2,500 ft² against a typical 1,089 ft²) and it is newer than 18% of them (1870 against a typical 1899). These shares are recounted nightly from the full county assessor record for each area, not from active listings.

What are the property taxes on 20 Monument Sq, Charlestown, MA?

The 2025 property tax bill for 20 Monument Sq, Charlestown, MA was $44,024. The county assessed it at $3,801,700.

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