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Single Family ResidenceResidential
$878,261$377 / 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 93How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Jul 14, 2026

21 S DUKE ST

ROCKVILLE, MD 20850
2.5
Baths
2,329 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.
0.23 ac
Lot SizeThe size of the land the home sits on, from county records.
1970
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
1
ParkingThe number of parking spaces on the property, including the garage.

Valuation

$878K
$814K low$943K high
Est. Owner EquityRoughly how much of the home's value the owner would keep after paying off known loans. It is our estimate minus the loans still owed.$878,261
Est. Lendable EquityThe part of the owner's equity a lender would typically let them borrow against — about 80% of their equity.$702,609

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$9,421 (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.$733,500 (2026)
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$699,000
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$768,000

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.Bi-Level
CountyMONTGOMERY
Lot (acres)The size of the land the home sits on, from county records.0.23
RoofThe main material covering the roof, such as asphalt shingle or tile.Composition Shingle
HeatingThe type of heating system in the home.Yes
CoolingThe type of cooling or air conditioning in the home.Central
FireplaceWhether the home has a fireplace, and what kind.Yes
GarageWhether the property has a garage, and details like whether it is attached to the home.Garage, Attached
PoolWhether the property has a pool, and what kind, such as in-ground.No
FeaturesExtra features found in county records. Records are not complete everywhere, so a missing feature does not always mean the home lacks it.Deck · 100 ft²Shed · 100 ft²Porch · 204 ft²

Transaction History(1)

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
College Gardens Elementary SchoolC-
Elementary · Grades PK–5 · 0.4 mi
M
Julius West Middle SchoolA
Middle · Grades 6–8 · 1.8 mi
H
Richard Montgomery High SchoolA-
High · Grades 9–12 · 2.0 mi

District: Montgomery County Public Schools

Neighborhood · ZIP 20850These 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.104
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.89
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.40

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.28%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.7.8%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.0.8%
PopulationHow many people live in this area.51,693
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.3,703 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$126,425
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$154,183
Average tempThe average temperature here across a full year.54°F
Annual precipHow much rain and melted snow falls here in a typical year.43 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.57%

Ownership

OccupancyWhether the owner appears to live here or somewhere else. It is inferred from the mailing address on record.Absentee owner
Company ownedWhether the owner is a company or trust rather than a person.Yes

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 S Duke 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 more than 74% of homes in Rockville
  • Costs more per square foot than 76% of homes in Montgomery County
  • Bigger than 68% of homes in Rockville
  • Has a bigger lot than 78% of homes in Rockville
  • Older than 70% of homes in Rockville 20850

What homes are worth in Rockville 20850

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

This home
$173K$1.6M

This home is worth more than 67% of homes in Rockville 20850.

How it measures up in Rockville 20850

The dot is this home. The mark in the middle is the typical home in Rockville 20850.

Estimated value$878,261
CheaperTypical $750,107Pricier

Pricier than 67% of homes nearby

Price per ft²$377
CheaperTypical $339Pricier

Pricier than 70% of homes nearby

Living area2,329 ft²
SmallerTypical 2,040 ft²Bigger

Bigger than 60% of homes nearby

Lot size0.23 ac
SmallerTypical 4,225 ft²Bigger

Bigger than 74% of homes nearby

Year built1970
OlderTypical 1991Newer

Newer than 30% of homes nearby

How 21 S Duke St ranks against every home in each area.
MeasureThis homeRockvilleRockville 20850Montgomery County
Estimated valuepricier than$878,26174% of homes67% of homes73% of homes
Price per ft²pricier than$37765% of homes70% of homes76% of homes
Living areabigger than2,329 ft²68% of homes60% of homes61% of homes
Lot sizebigger than0.23 ac78% of homes74% of homes66% of homes
Year builtnewer than197046% of homes30% of homes39% of homes

About 21 S Duke St

How much is 21 S Duke St, Rockville, MD worth?

The TopHap Estimate for 21 S Duke St, Rockville, MD is $878,261 as of Jul 14, 2026. The likely range is $813,886 to $942,636. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 21 S Duke St, Rockville, MD last sell?

21 S Duke St, Rockville, MD last sold on Jan 1, 1900, according to the county's recorded deed.

How big is 21 S Duke St, Rockville, MD?

21 S Duke St, Rockville, MD has 2.5 bathrooms, 2,329 square feet of living space and a 0.23-acre lot.

When was 21 S Duke St, Rockville, MD built?

21 S Duke St, Rockville, MD was built in 1970, making it 56 years old. It is a bi-level home. The building has 2 stories.

What schools serve 21 S Duke St, Rockville, MD?

21 S Duke St, Rockville, MD is assigned to College Gardens Elementary School (elementary), rated C-; Julius West Middle School (middle), rated A; Richard Montgomery High School (high), rated A-. All sit in Montgomery County Public Schools. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21 S Duke St, Rockville, MD compare to other homes in Rockville 20850?

Among the 14,094 homes in Rockville 20850, it is worth more than 67% of them ($878,261 against a typical $750,107), its price per square foot is higher than 70% of them ($377 against a typical $339), it is bigger than 60% of them (2,329 ft² against a typical 2,040 ft²), its lot is bigger than 74% of them (0.23 ac against a typical 4,225 ft²) and it is newer than 30% of them (1970 against a typical 1991). Measured against all of Montgomery County, it is worth more than 73% 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 S Duke St, Rockville, MD?

The 2025 property tax bill for 21 S Duke St, Rockville, MD was $9,421. The county assessed it at $733,500.

Closest homes

More homes in Rockville 20850

Assigned schools

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