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Single Family ResidenceResidential
$731,136$599 / 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 95How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Jun 23, 2026
Last sold for $135,790 on Dec 12, 1986

12421 ROCK RIDGE RD

HERNDON, VA 20170
5
Beds
3
Baths
1,220 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.
0.29 ac
Lot SizeThe size of the land the home sits on, from county records.
1986
Year BuiltThe year the home was originally built, according to county records.
1
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.
1
ParkingThe number of parking spaces on the property, including the garage.

Valuation

$731K
$695K low$768K high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$135,790 · Dec 12, 1986
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.$731,136
Est. Lendable EquityThe part of the owner's equity a lender would typically let them borrow against — about 80% of their equity.$584,909

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$7,293 (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.$630,890 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$246,000
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$384,890
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$582,210
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$630,890

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.Split Entry
CountyFairfax
Lot (acres)The size of the land the home sits on, from county records.0.29
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.Composition Shingle
HeatingThe type of heating system in the home.Heat Pump
CoolingThe type of cooling or air conditioning in the home.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.BalconyDeck · 200 ft²Patio · 360 ft²

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

E
Dranesville Elementary SchoolC
Elementary · Grades PK–6 · 0.5 mi
H
Herndon High SchoolD-
High · Grades 9–12 · 0.8 mi
M
Herndon Middle SchoolD
Middle · Grades 7–8 · 2.1 mi

District: Fairfax County Public Schools

Neighborhood · ZIP 20170These 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.68
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.78
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.98%
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.6.1%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.0%
PopulationHow many people live in this area.43,831
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.4,979 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$149,422
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$172,691
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.63%

Ownership

OccupancyWhether the owner appears to live here or somewhere else. It is inferred from the mailing address on record.Owner occupied
Company ownedWhether the owner is a company or trust rather than a person.No

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

12421 Rock Ridge Rd 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.

  • Costs more per square foot than 97% of homes in Herndon 20170
  • Smaller than 83% of homes in Herndon 20170
  • Has a bigger lot than 78% of homes in Herndon 20170

What homes are worth in Herndon 20170

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

This home
$285K$1.6M

This home is worth more than 55% of homes in Herndon 20170.

How it measures up in Herndon 20170

The dot is this home. The mark in the middle is the typical home in Herndon 20170.

Estimated value$731,136
CheaperTypical $704,925Pricier

Pricier than 55% of homes nearby

Price per ft²$599
CheaperTypical $372Pricier

Pricier than 97% of homes nearby

Living area1,220 ft²
SmallerTypical 1,656 ft²Bigger

Bigger than 17% of homes nearby

Lot size0.29 ac
SmallerTypical 0.22 acBigger

Bigger than 78% of homes nearby

Year built1986
OlderTypical 1983Newer

Newer than 61% of homes nearby

How 12421 Rock Ridge Rd ranks against every home in each area.
MeasureThis homeHerndon 20170Fairfax County
Estimated valuepricier than$731,13655% of homes44% of homes
Price per ft²pricier than$59997% of homes88% of homes
Living areabigger than1,220 ft²17% of homes22% of homes
Lot sizebigger than0.29 ac78% of homes66% of homes
Year builtnewer than198661% of homes63% of homes

About 12421 Rock Ridge Rd

How much is 12421 Rock Ridge Rd, Herndon, VA worth?

The TopHap Estimate for 12421 Rock Ridge Rd, Herndon, VA is $731,136 as of Jun 23, 2026. The likely range is $694,579 to $767,692. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 12421 Rock Ridge Rd, Herndon, VA last sell?

12421 Rock Ridge Rd, Herndon, VA last sold on Dec 12, 1986 for $135,790, according to the county's recorded deed.

How big is 12421 Rock Ridge Rd, Herndon, VA?

12421 Rock Ridge Rd, Herndon, VA has 5 bedrooms, 3 bathrooms, 1,220 square feet of living space and a 0.29-acre lot.

When was 12421 Rock Ridge Rd, Herndon, VA built?

12421 Rock Ridge Rd, Herndon, VA was built in 1986, making it 40 years old. It is a split entry home. The building has 1 story.

What schools serve 12421 Rock Ridge Rd, Herndon, VA?

12421 Rock Ridge Rd, Herndon, VA is assigned to Dranesville Elementary School (elementary), rated C; Herndon High School (high), rated D-; Herndon Middle School (middle), rated D. All sit in Fairfax County Public Schools. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 12421 Rock Ridge Rd, Herndon, VA compare to other homes in Herndon 20170?

Among the 11,448 homes in Herndon 20170, it is worth more than 55% of them ($731,136 against a typical $704,925), its price per square foot is higher than 97% of them ($599 against a typical $372), it is bigger than 17% of them (1,220 ft² against a typical 1,656 ft²), its lot is bigger than 78% of them (0.29 ac against a typical 0.22 ac) and it is newer than 61% of them (1986 against a typical 1983). Measured against all of Fairfax County, it is worth more than 44% 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 12421 Rock Ridge Rd, Herndon, VA?

The 2025 property tax bill for 12421 Rock Ridge Rd, Herndon, VA was $7,293. The county assessed it at $630,890.

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Assigned schools

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