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Single Family ResidenceResidential
$972,757$239 / 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 Oct 21, 2026
Last sold for $439,900 on Jul 13, 2010

3900 OBSIDIAN LN

ROUND ROCK, TX 78681
3.5
Baths
4,073 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.
2010
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

$973K
$938K low$1M high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$439,900 · Jul 13, 2010

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$14,850 (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.$955,810 (2025)
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$868,918
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$990,098

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.0.28
HeatingThe type of heating system in the home.Central
CoolingThe type of cooling or air conditioning in the home.Central
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 · 161 ft²

Transaction History(2)

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
Walsh Middle SchoolA+
Middle · Grades 6–8 · 0.2 mi
E
Cactus Ranch Elementary SchoolA+
Elementary · Grades KG–5 · 1.0 mi
H
Round Rock High SchoolA
High · Grades 9–12 · 2.9 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.72,546
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

3900 Obsidian 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 more than 98% of homes in Williamson County
  • Costs more per square foot than 84% of homes in Round Rock 78681
  • Bigger than 97% of homes in Williamson County
  • Has a bigger lot than 80% of homes in Round Rock 78681
  • Newer than 85% 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
$240K$1M

This home is worth more than 97% 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$972,757
CheaperTypical $480,575Pricier

Pricier than 97% of homes nearby

Price per ft²$239
CheaperTypical $212Pricier

Pricier than 84% of homes nearby

Living area4,073 ft²
SmallerTypical 2,332 ft²Bigger

Bigger than 96% of homes nearby

Lot size0.29 ac
SmallerTypical 0.2 acBigger

Bigger than 80% of homes nearby

Year built2010
OlderTypical 1999Newer

Newer than 85% of homes nearby

How 3900 Obsidian Ln ranks against every home in each area.
MeasureThis homeRound Rock 78681Williamson County
Estimated valuepricier than$972,75797% of homes98% of homes
Price per ft²pricier than$23984% of homes84% of homes
Living areabigger than4,073 ft²96% of homes97% of homes
Lot sizebigger than0.29 ac80% of homes73% of homes
Year builtnewer than201085% of homes56% of homes

About 3900 Obsidian Ln

How much is 3900 Obsidian Ln, Round Rock, TX worth?

The TopHap Estimate for 3900 Obsidian Ln, Round Rock, TX is $972,757 as of Oct 21, 2026. The likely range is $938,128 to $1,007,386. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 3900 Obsidian Ln, Round Rock, TX last sell?

3900 Obsidian Ln, Round Rock, TX last sold on Jul 13, 2010 for $439,900, according to the county's recorded deed.

How big is 3900 Obsidian Ln, Round Rock, TX?

3900 Obsidian Ln, Round Rock, TX has 3.5 bathrooms, 4,073 square feet of living space and a 0.28-acre lot.

When was 3900 Obsidian Ln, Round Rock, TX built?

3900 Obsidian Ln, Round Rock, TX was built in 2010, making it 16 years old. The building has 2 stories.

What schools serve 3900 Obsidian Ln, Round Rock, TX?

3900 Obsidian Ln, Round Rock, TX is assigned to Walsh Middle School (middle), rated A+; Cactus Ranch Elementary School (elementary), rated A+; Round Rock High School (high), rated A. All sit in Round Rock Independent School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 3900 Obsidian Ln, Round Rock, TX compare to other homes in Round Rock 78681?

Among the 17,728 homes in Round Rock 78681, it is worth more than 97% of them ($972,757 against a typical $480,575), its price per square foot is higher than 84% of them ($239 against a typical $212), it is bigger than 96% of them (4,073 ft² against a typical 2,332 ft²), its lot is bigger than 80% of them (0.29 ac against a typical 0.2 ac) and it is newer than 85% of them (2010 against a typical 1999). Measured against all of Williamson County, it is worth more than 98% 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 3900 Obsidian Ln, Round Rock, TX?

The 2025 property tax bill for 3900 Obsidian Ln, Round Rock, TX was $14,850. The county assessed it at $955,810.

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