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Single Family ResidenceResidential
$586,147$177 / 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 96How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Aug 30, 2026
Last sold for $550,000 on Mar 17, 2021

3821 DERBY TRL

ROUND ROCK, TX 78681
3.5
Baths
3,317 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.
0.15 ac
Lot SizeThe size of the land the home sits on, from county records.
2005
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
2
ParkingThe number of parking spaces on the property, including the garage.

Valuation

$586K
$564K low$608K high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$550,000 · Mar 17, 2021

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$12,999 (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.$575,915 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$107,000
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$468,915
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$652,200
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$575,915

Climate Risk

Projected Flood DepthHow deep a serious flood is expected to get here at some point in the next 30 years. Shown in inches.17 in
30-Year Flood ChanceThe chance of at least one serious flood here in the next 30 years, not in any single year.30%
FEMA Flood ZoneFEMA's flood zone for this address. Zones starting with A or V are high risk, and lenders usually require flood insurance there.minimal

Scores 0–100; higher = greater projected risk.

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
CountyWILLIAMSON
Lot (acres)The size of the land the home sits on, from county records.0.15
HeatingThe type of heating system in the home.Central
CoolingThe type of cooling or air conditioning in the home.Central
FireplaceWhether the home has a fireplace, and what kind.Yes
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.Porch · 166 ft²

Transaction History(3)

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.

M
Stiles Middle SchoolA+
Middle · Grades 6–8 · 2.5 mi
E
Akin Elementary SchoolA-
Elementary · Grades KG–5 · 2.5 mi
H
Rouse High SchoolA-
High · Grades 9–12 · 4.3 mi

District: Leander Independent School District

Neighborhood · ZIP 78681These 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.44
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.86
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.20

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.38%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.4.9%
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.72,546
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.3,224 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$126,547
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$146,868
Average tempThe average temperature here across a full year.67°F
Annual precipHow much rain and melted snow falls here in a typical year.35 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.60%

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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

3821 Derby Trl 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 81% of homes in Williamson County
  • Costs less per square foot than 95% of homes in Round Rock 78681
  • Bigger than 90% of homes in Williamson County
  • Has a smaller lot than 87% of homes in Mayfield Ranch
  • Older than 81% of homes in Mayfield Ranch

What homes are worth in Round Rock 78681

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

This home
$269K$1.1M

This home is worth more than 68% of homes in Round Rock 78681.

How it measures up in Round Rock 78681

The dot is this home. The mark in the middle is the typical home in Round Rock 78681.

Estimated value$586,147
CheaperTypical $492,910Pricier

Pricier than 68% of homes nearby

Price per ft²$177
CheaperTypical $216Pricier

Pricier than 5% of homes nearby

Living area3,317 ft²
SmallerTypical 2,322 ft²Bigger

Bigger than 86% of homes nearby

Lot size0.15 ac
SmallerTypical 0.2 acBigger

Bigger than 14% of homes nearby

Year built2005
OlderTypical 1999Newer

Newer than 76% of homes nearby

How 3821 Derby Trl ranks against every home in each area.
MeasureThis homeMayfield RanchRound Rock 78681Williamson County
Estimated valuepricier than$586,14774% of homes68% of homes81% of homes
Price per ft²pricier than$1777% of homes5% of homes27% of homes
Living areabigger than3,317 ft²89% of homes86% of homes90% of homes
Lot sizebigger than0.15 ac13% of homes14% of homes19% of homes
Year builtnewer than200519% of homes76% of homes46% of homes

About 3821 Derby Trl

How much is 3821 Derby Trl, Round Rock, TX worth?

The TopHap Estimate for 3821 Derby Trl, Round Rock, TX is $586,147 as of Aug 30, 2026. The likely range is $564,051 to $608,243. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 3821 Derby Trl, Round Rock, TX last sell?

3821 Derby Trl, Round Rock, TX last sold on Mar 17, 2021 for $550,000, according to the county's recorded deed.

How big is 3821 Derby Trl, Round Rock, TX?

3821 Derby Trl, Round Rock, TX has 3.5 bathrooms, 3,317 square feet of living space and a 0.15-acre lot.

When was 3821 Derby Trl, Round Rock, TX built?

3821 Derby Trl, Round Rock, TX was built in 2005, making it 21 years old. The building has 2 stories.

What schools serve 3821 Derby Trl, Round Rock, TX?

3821 Derby Trl, Round Rock, TX is assigned to Stiles Middle School (middle), rated A+; Akin Elementary School (elementary), rated A-; Rouse High School (high), rated A-. All sit in Leander Independent School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 3821 Derby Trl, Round Rock, TX compare to other homes in Round Rock 78681?

Among the 18,026 homes in Round Rock 78681, it is worth more than 68% of them ($586,147 against a typical $492,910), its price per square foot is higher than 5% of them ($177 against a typical $216), it is bigger than 86% of them (3,317 ft² against a typical 2,322 ft²), its lot is bigger than 14% of them (0.15 ac against a typical 0.2 ac) and it is newer than 76% of them (2005 against a typical 1999). Measured against all of Williamson County, it is worth more than 81% 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 3821 Derby Trl, Round Rock, TX?

The 2025 property tax bill for 3821 Derby Trl, Round Rock, TX was $12,999. The county assessed it at $575,915.

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