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Single Family ResidenceResidential
$81,342$164 / 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 67How 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 $25,000 on Feb 24, 2016

509 WILLIAM ST

ALTON, IL 62002
1
Baths
495 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.
2,829 ft²
Lot SizeThe size of the land the home sits on, from county records.
1834
Year BuiltThe year the home was originally built, according to county records.
1
StoriesHow many floors the home has above ground.

Valuation

$81K
$54K low$108K high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$25,000 · Feb 24, 2016

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$1,129 (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.$30,720 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$2,410
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$28,310
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$27,790
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$92,160

Climate Risk

Overall riskThe average of the five hazard scores below, on a 0 to 100 scale. Higher means greater projected risk over the coming decades.35
1
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
18
WildfireProjected wildfire risk, scored 0 to 100, based on how much land burns in a typical year. Higher is riskier.
83
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
70
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
4
DroughtProjected water shortage risk, scored 0 to 100. Higher means more strain on the local water supply.

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
CountyMADISON
Lot (acres)The size of the land the home sits on, from county records.0.07
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.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
PoolWhether the property has a pool, and what kind, such as in-ground.No

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.

Foreclosure Filings(2)

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

M
Alton Middle SchoolC-
Middle · Grades 6–8 · 2.0 mi
E
Gilson Brown Elementary School
Elementary · Grades KG–1 · 3.1 mi
H
Alton High SchoolD+
High · Grades 9–12 · 3.4 mi

District: Alton Community Unit School District 11

Neighborhood · ZIP 62002These 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.135
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.85
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.125

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.89%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.16%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.19%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.1%
PopulationHow many people live in this area.28,813
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.738 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$61,207
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$78,082
Average tempThe average temperature here across a full year.55°F
Annual precipHow much rain and melted snow falls here in a typical year.39 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.59%

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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

509 William 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 less than 85% of homes in Madison County
  • Costs more per square foot than 79% of homes in Alton 62002
  • Among the smallest homes in Alton 62002
  • Among the smallest lots in Madison County
  • Among the oldest homes in Alton 62002

What homes are worth in Alton 62002

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

This home
$23K$442K

This home is worth more than 35% of homes in Alton 62002.

How it measures up in Alton 62002

The dot is this home. The mark in the middle is the typical home in Alton 62002.

Estimated value$81,342
CheaperTypical $107,151Pricier

Pricier than 35% of homes nearby

Price per ft²$164
CheaperTypical $107Pricier

Pricier than 79% of homes nearby

Living area495 ft²
SmallerTypical 1,008 ft²Bigger

Smaller than almost all homes nearby

Lot size2,829 ft²
SmallerTypical 0.19 acBigger

Smaller than almost all homes nearby

Year built1834
OlderTypical 1948Newer

Older than almost all homes nearby

How 509 William St ranks against every home in each area.
MeasureThis homeAlton 62002Madison County
Estimated valuepricier than$81,34235% of homes15% of homes
Price per ft²pricier than$16479% of homes52% of homes
Living areabigger than495 ft²almost no homesalmost no homes
Lot sizebigger than2,829 ft²almost no homesalmost no homes
Year builtnewer than1834almost no homesalmost no homes

About 509 William St

How much is 509 William St, Alton, IL worth?

The TopHap Estimate for 509 William St, Alton, IL is $81,342 as of Aug 30, 2026. The likely range is $54,461 to $108,223. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 509 William St, Alton, IL last sell?

509 William St, Alton, IL last sold on Feb 24, 2016 for $25,000, according to the county's recorded deed. TopHap holds 2 recorded sales for this parcel.

How big is 509 William St, Alton, IL?

509 William St, Alton, IL has 1 bathrooms, 495 square feet of living space and a 0.07-acre lot.

When was 509 William St, Alton, IL built?

509 William St, Alton, IL was built in 1834, making it 192 years old. The building has 1 story.

What schools serve 509 William St, Alton, IL?

509 William St, Alton, IL is assigned to Alton Middle School (middle), rated C-; Gilson Brown Elementary School (elementary); Alton High School (high), rated D+. All sit in Alton Community Unit School District 11. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 509 William St, Alton, IL compare to other homes in Alton 62002?

Among the 12,598 homes in Alton 62002, it is worth more than 35% of them ($81,342 against a typical $107,151), its price per square foot is higher than 79% of them ($164 against a typical $107), it is bigger than almost none of them (495 ft² against a typical 1,008 ft²), its lot is bigger than almost none of them (2,829 ft² against a typical 0.19 ac) and it is newer than almost none of them (1834 against a typical 1948). Measured against all of Madison County, it is worth more than 15% 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 509 William St, Alton, IL?

The 2025 property tax bill for 509 William St, Alton, IL was $1,129. The county assessed it at $30,720.

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Assigned schools

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