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Single Family ResidenceResidential
$483,797$200 / 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

3521 SHELLCASTLE LN

ROUND ROCK, TX 78681
3 / 1
Baths
2,424 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.
0.18 ac
Lot SizeThe size of the land the home sits on, from county records.
2006
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

$484K
$460K low$508K 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.$283,797
Est. Lendable EquityThe part of the owner's equity a lender would typically let them borrow against — about 80% of their equity.$227,038
Loan-to-ValueHow much is still owed on the home compared to what it is worth. 80% means loans equal 80% of our estimate, so it shifts when the estimate does.41%
1st MortgageA loan still believed to be open on this home, in the order lenders get repaid. The first position is paid back before the second.$200,000
LOAN CABIN INC · recorded Apr 30, 2021

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$9,575 (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.$519,858 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$120,000
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$399,858
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$519,858
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$519,858

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
CountyWilliamson
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.2008
FoundationWhat the home is built on, such as a concrete slab, a crawl space, or a basement.Mat/Raft Foundation (Slab)
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.Deck · 503 ft²Porch · 121 ft²

Transaction History(4)

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
Chandler Oaks Elementary SchoolA+
Elementary · Grades KG–5 · 0.6 mi
M
Walsh Middle SchoolA
Middle · Grades 6–8 · 1.4 mi
H
Stony Point High SchoolC+
High · Grades 9–12 · 5.0 mi

District: Round Rock 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.72,545
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%

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.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

3521 Shellcastle Ln 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 less than 67% of homes in Mayfield Ranch
  • Costs less per square foot than 77% of homes in Round Rock 78681
  • Newer than 79% of homes in Round Rock 78681

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
$256K$1.1M

This home is worth more than 46% 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$483,797
CheaperTypical $498,013Pricier

Pricier than 46% of homes nearby

Price per ft²$200
CheaperTypical $219Pricier

Pricier than 23% of homes nearby

Living area2,424 ft²
SmallerTypical 2,315 ft²Bigger

Bigger than 56% of homes nearby

Lot size0.18 ac
SmallerTypical 0.2 acBigger

Bigger than 36% of homes nearby

Year built2006
OlderTypical 1998Newer

Newer than 79% of homes nearby

How 3521 Shellcastle Ln ranks against every home in each area.
MeasureThis homeMayfield RanchRound Rock 78681Williamson County
Estimated valuepricier than$483,79733% of homes46% of homes66% of homes
Price per ft²pricier than$20044% of homes23% of homes48% of homes
Living areabigger than2,424 ft²38% of homes56% of homes64% of homes
Lot sizebigger than0.18 ac54% of homes36% of homes36% of homes
Year builtnewer than200628% of homes79% of homes49% of homes

About 3521 Shellcastle Ln

How much is 3521 Shellcastle Ln, Round Rock, TX worth?

The TopHap Estimate for 3521 Shellcastle Ln, Round Rock, TX is $483,797 as of Jun 23, 2026. The likely range is $459,607 to $507,986. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 3521 Shellcastle Ln, Round Rock, TX last sell?

3521 Shellcastle Ln, Round Rock, TX last sold on Apr 27, 2016, according to the county's recorded deed.

How big is 3521 Shellcastle Ln, Round Rock, TX?

3521 Shellcastle Ln, Round Rock, TX has 3 bathrooms and 2,424 square feet of living space.

When was 3521 Shellcastle Ln, Round Rock, TX built?

3521 Shellcastle Ln, Round Rock, TX was built in 2006, making it 20 years old. The building has 2 stories.

What schools serve 3521 Shellcastle Ln, Round Rock, TX?

3521 Shellcastle Ln, Round Rock, TX is assigned to Chandler Oaks Elementary School (elementary), rated A+; Walsh Middle School (middle), rated A; Stony Point High School (high), rated C+. All sit in Round Rock Independent School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 3521 Shellcastle Ln, Round Rock, TX compare to other homes in Round Rock 78681?

Among the 18,081 homes in Round Rock 78681, it is worth more than 46% of them ($483,797 against a typical $498,013), its price per square foot is higher than 23% of them ($200 against a typical $219), it is bigger than 56% of them (2,424 ft² against a typical 2,315 ft²), its lot is bigger than 36% of them (0.18 ac against a typical 0.2 ac) and it is newer than 79% of them (2006 against a typical 1998). Measured against all of Williamson County, it is worth more than 66% 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 3521 Shellcastle Ln, Round Rock, TX?

The 2025 property tax bill for 3521 Shellcastle Ln, Round Rock, TX was $9,575. The county assessed it at $519,858.

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Assigned schools

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